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PubMed2025

Noninvasive preimplantation genetic testing for aneuploidy using blastocyst spent culture medium may serve as a backup of trophectoderm biopsy in conventional preimplantation genetic testing.

BACKGROUND: To investigate whether the noninvasive preimplantation genetic testing (niPGT) complement conventional preimplantation genetic testing (PGT) in the embryos for aneuploidy. RESULTS: 40 spent culture medium (SCM) samples from routine embryo culture were collected, and half of each SCM (10 µL) sample was used for whole genome amplification, while the other half was stored at -80 °C for 3-6 months. Thirty-six out of 40 fresh SCM samples were successfully amplified and sequenced. Thirty-six paired frozen-thawed SCM samples showed 100% concordance with the freshly amplified SCM samples. Then, SCM and trophectoderm (TE) samples from 149 blastocysts from 51 couples were collected. A 98.0% successful SCM sample amplification rate (146/149) was achieved. For the 146 paired TE biopsy and SCM samples, the overall concordance rate was 82.9% (121/146). Ten embryos with aneuploid TE results but euploid niPGT results were donated. A 70.0% (7/10) true negative rate was achieved by niPGT with respect to the inner cell mass (ICM) results (TE-positive embryos). CONCLUSIONS: These results suggested that SCM stored at -80 °C for 6 months without affecting niPGT results based on NICSInst amplification.

Humans↗

PubMed2026

Prospective clinical validation of targeted long-read sequencing for preimplantation genetic testing of α-thalassaemia.

BACKGROUND: Preimplantation genetic testing for monogenic disorders (PGT-M) can prevent transmission of severe α-thalassaemia, but conventional workflows remain limited by family-specific assay design for direct variant detection, dependence on additional family samples for haplotype construction, and labour-intensive multi-step procedures across several platforms. Targeted long-read sequencing-based PGT-M for α-thalassaemia (tlrPGT-α-thal) integrates direct variant detection and haplotype linkage analysis within a single assay, but prospective clinical validation is lacking. METHODS: This prospective clinical study enrolled 103 families at high risk of transmitting α-thalassaemia at a reproductive medicine centre between August 2024 and March 2025. All families underwent blinded parallel analysis using both conventional NGS-based PGT-M (comparator) and tlrPGT-α-thal. RESULTS: In the primary concordance analysis, tlrPGT-α-thal was fully concordant with conventional NGS-based PGT-M (507/507, 100.0%; exact 95% CI, 99.3-100.0). Direct variant detection was successful in 501/507 embryos (98.82%; 95% CI, 97.4-99.6), haplotype linkage was established in 505/507 embryos (99.61%; 95% CI, 98.6-100.0), and one meiotic recombination event was identified. Among 93 families proceeding to embryo transfer, 57 pregnancies underwent invasive prenatal diagnosis, and all were concordant with the corresponding tlrPGT-α-thal results. Of the 26 comparator-inconclusive embryos, tlrPGT-α-thal resolved 6 complex cases, including cases with incomplete pedigrees or insufficient informative SNPs. Among the remaining 20 embryos with HBA-region aneuploidies, genotype and parental origin could be determined in 12. CONCLUSIONS: The findings show that tlrPGT-α-thal enables direct detection of diverse α-thalassaemia-causing variants together with efficient haplotype linkage analysis within a single workflow, without requiring family-specific assay design or additional family samples. The method demonstrated high diagnostic accuracy while providing added value in complex scenarios. Taken together, tlrPGT-α-thal represents a simplified and broadly applicable strategy for α-thalassaemia PGT-M.

Humans↗

PubMed2026

IVF patient subgroups benefit from preimplantation genetic testing for aneuploidy: a prospective multicentre cohort study.

RESEARCH QUESTION: Can preimplantation genetic testing for aneuploidy (PGT-A) improve the ongoing pregnancy rate per transfer and reduce miscarriage rate in patients with advanced maternal age (AMA), recurrent implantation failure (RIF), recurrent pregnancy loss (RPL), or both, without affecting cumulative pregnancy rate? DESIGN: Prospective cohort study of 260 patients undergoing PGT-A aged 36 years or over (AMA group), with a history of three or more blastocyst transfers without birth (RIF group), two or more early pregnancy losses (RPL group), or all. Trophectoderm biopsy was conducted day 5 or 6, and comprehensive chromosome screening was used for PGT-A before single frozen embryo transfer (PGT-A-FET). A total of 3060 patients undergoing single conventional frozen embryo transfer (FET) served as a historical reference group. RESULTS: Patients had increased odds of positive serum beta-HCG after PGT-A-FET compared with FET in the AMA (OR 1.53, 95% CI 1.06 to 2.21) and RIF (OR 2.11, 95% CI 1.41 to 3.14) groups. The PGT-A-FET group significantly improved the odds of ongoing pregnancy in the AMA (OR 2.20, 95% CI 1.52 to 3.18), RIF (OR 3.96, 95% CI 2.60 to 6.04) and RPL (OR 2.81, 95% CI 1.52 to 5.21) groups. The odds of pregnancy loss were significantly reduced with PGT-A-FET in the AMA (OR 0.36, 95% CI 0.21 to 0.64), RIF (OR 0.10, 95% CI 0.04 to 0.26) and RPL (OR 0.14, 95% CI 0.04 to 0.53) groups. Cumulative pregnancy rate did not differ between PGT-A and conventional cycles (RR 0.94, 95% CI 0.80 to 1.10). CONCLUSIONS: PGT-A improved the odds of ongoing pregnancy and reduced the odds of pregnancy loss in all groups. The cumulative pregnancy rate did not differ between PGT-A and conventional cycles. Findings should be interpreted in the context of the observational design.

Adult↗

PubMed2025

Accurate identification of abnormal ploidy using an artificial intelligence model in preimplantation genetic testing.

STUDY QUESTION: Can ultra-low-coverage whole-genome sequencing (ulc-WGS) accurately identify abnormal ploidy during preimplantation genetic testing (PGT)? SUMMARY ANSWER: The artificial intelligence (AI)-based PGT-Plus model demonstrates high accuracy in ploidy detection, offering a cost-effective solution that enhances clinical utility of PGT. WHAT IS KNOWN ALREADY: The predominant PGT for aneuploidy can identify chromosomal aneuploidies but cannot determine ploidy status. Transferring embryos with ploidy abnormalities can result in miscarriage and molar pregnancy. On the other hand, in ART, fertilization is assessed by morphological pronuclear assessment at the zygote stage. However, it has a low specificity in the prediction of abnormal ploidy status and embryos deemed abnormally fertilized can yield healthy pregnancies. Accurately identified abnormal ploidy in PGT-A can resolve current limitations and expand the utility range of PGT-A. Several studies have identified ploidy abnormalities; however, they were mainly based on single-nucleotide polymorphism (SNP) arrays or needed to combine additional targeted-next-generation sequencing (NGS) information. Studies based on ulc-WGS remain scarce. STUDY DESIGN SIZE DURATION: The study consisted of two stages: methodology establishment and validation. An AI model, named PGT-Plus, was developed using 653 samples with known ploidy status, which was further validated using 792 different ploidy status samples. In the clinical application stage, the approach was used to analyse the ploidy status of 19 103 normally fertilized PGT blastocysts and 140 single pronucleus (1PN)-derived blastocysts collected between May 2022 and December 2023. All blastocysts were tested using trophectoderm biopsy and NGS. PARTICIPANTS/MATERIALS SETTING METHODS: The methodology is based on the ulc-WGS data. First, based on samples with known ploidy status: the heterozygosity rate of high-frequency biallelic SNPs, the likelihood ratio (LLR) of alleles was calculated under different assumptions ('both parental homologs' [BPH] from a single parent, 'single parental homolog' [SPH] from each parent, disomy, and monosomy) by leveraging allele frequencies and linkage disequilibrium (LD) measured in the 1000 genomes project database. Twenty-three continuous candidate features derived from heterozygosity rates and LLRs of chromosomes or selected windows were included to establish the ploidy prediction AI model. Gini importance analysis and multicollinearity mitigation was performed for feature selection, then the performance of Random Forest (RF), Support Vector Machine (SVM), and Logistic Regression for modelling was compared. Subsequently, the parameter optimization was performed based on the RF model. Ploidy constitution concordance was evaluated in known ploidy status samples. The frequency of abnormal ploidy in normal fertilized PGT blastocysts and 1PN-derived blastocysts (including conventional IVF and ICSI) was evaluated. MAIN RESULTS AND THE ROLE OF CHANCE: Eleven features were collected for model architecture compared to SVM and Logistic Regression; RF achieved superior performance for ploidy detection. The AI model achieved an AUC of 1 for genome-wide-uniparental diploidy (GW-UPD), 1 for triploidy, and 0.99 for diploidy. For the 792 validation samples, 99.5% of samples were successfully detected using the AI model, and the model showed 100% accuracy for ploidy classification. In the clinical application stage, out of 19 103 PGT samples, 19 069 were successfully analysed using the model, with 110 (0.57%) identified as having abnormal ploidy embryos. Among these, 12.7% (14/110) were identified as GW-UPD, and 87.3% (96/110) were triploid. Among 5563 diploid blastocysts transferred, 3478 clinical pregnancies were achieved. Subsequent ploidy analysis was performed for 217 spontaneous abortion and 935 prenatal diagnostic samples, and no abnormal ploidy was identified. Furthermore, of the 140 1PN embryos tested, 40 (28.6%) exhibited GW-UPD, 3 (2.1%) exhibited triploidy, and 97 (69.3%) were determined to be biparental and normally fertilized. Among the 97 biparental embryos, 46 were diploid, 11 were mosaic, and 40 were aneuploid. In terms of the insemination pattern, the percentage of abnormal ploidy in ICSI was significantly higher than in conventional IVF (P < 0.01, 37.1% vs. 2.9%, respectively). With full informed consent, 20 patients without euploidy from normal fertilization chose 1PN-derived biparental and diploid blastocysts to transfer, resulting in 10 clinical pregnancies and 9 ongoing pregnancies. LARGE-SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: Some rare ploidy abnormalities, such as polyploidy with an equal number of identical sets of chromosomes and ploidy mosaicism cannot be accurately identified. Moreover, the origin of abnormal ploidy was not identified due to the unavailability of DNA from both parents. WIDER IMPLICATIONS OF THE FINDINGS: The PGT-Plus AI model provides a ploidy evaluation method based on the conventional PGT-A data and integrates directly into standard PGT-A workflows. Clinical utility results suggest that the model is a valuable tool for identifying embryos with abnormal ploidy in PGT-A and rescuing normal diploid embryos from abnormally fertilized embryos. These findings demonstrate that PGT-Plus significantly enhances the diagnostic accuracy of PGT. STUDY FUNDING/COMPETING INTERESTS: This study was supported by grants from Major Scientific Program of CITIC Group (No. 2023ZXKYB34100, to Ge.L.), Hunan Provincial Grant for Innovative Province Construction (2019SK4012), Hunan Xiangjiang New District (Changsha High-tech Zone) key core technology research project in 2023, and Science Foundation of Hunan Province (Grant 2023JJ30422). All authors declared no conflicts of interest..

artificial intelligence↗

PubMed2024

A healthy live birth after mosaic blastocyst transfer in preimplantation genetic testing for GATA1-related cytopenia combined with HLA matching.

BACKGROUND: GATA1-related cytopenia (GRC) is characterized by thrombocytopaenia and/or anaemia ranging from mild to severe. Haematopoietic stem cell transplantation (HSCT) is a healing therapeutic choice for GRC patients. We identified a novel pathogenic variant (GATA1: c.1019delG) in a boy with GATA1-related cytopenia. Then we performed preimplantation genetic testing (PGT) in this GRC family. After a mosaic embryo transfered, a healthy and HLA-compatible with the proband baby was delivered. CASE PRESENTATION: The proband is a 6-year-old boy who was diagnosed to have transfusion-dependent anaemia since 3 year old. Whole-exome sequencing (WES) showed that the proband has a hemizygous variant c.1019delG in GATA1, which is inherited from his mother. His parents decided to undergo PGT to have a health and HLA-compatible offspring. After whole genome amplification (WGA) of biopsied trophectoderm (TE) cells, next generation sequencing (NGS)-based PGT was preformed to analyse embryos on chromosomal aneuploidy, target mutation and HLA typing. There were 3 embryos HLA-matched to the proband. The genotypes of the 3 embryos were heterozygous variant, hemizygous variant, normal respectively. After a heterozygous, mosaic partial trisomy (chr)16, and HLA-matched embryo transfer, a healthy baby was delivered and whose HSCT is compatible with the proband. CONCLUSIONS: NGS-based PGT-HLA is a valuable procedure for the treatment of GATA1-related cytopenia caused by GATA1 variants, or other haematological disorders, oncological and immunological diseases. Furthermore, our study reconfirms that mosaic embryos transfer would bring healthy offspring.

Child↗

PubMed2026

A Comprehensive Survey and Evaluation of Preimplantation Genetic Testing Practices in Canadian Assisted Reproductive Technology Clinics.

OBJECTIVES: In Canada, access to provincial funding for fertility treatments, such as in vitro fertilization (IVF) and preimplantation genetic testing (PGT), vary significantly. Despite rising demands, the lack of data on current practices across Canadian assisted reproductive technology (ART) clinics has contributed to the absence of standardized guidelines to support clinics offering these services. This pilot study surveys fertility clinics to examine current demands and practices related to PGT, while also exploring providers' perspectives on its implementation and future applications. METHODS: A 40-question survey was distributed to Canadian ART clinics offering IVF and PGT services. RESULTS: The responses confirm that there is a high demand for IVF and PGT services. Although clinical criteria for PGT for aneuploidy (PGT-A) were generally consistent across clinics, views on its effectiveness and eligibility for public funding varied. PGT for monogenic disorders (PGT-M) appears to be widely available, and respondents showed strong support for public funding in cases involving serious heritable conditions. CONCLUSIONS: This study outlines current practice and highlights variations across clinics, while also presenting the perspectives of providers of ART clinics throughout Canada. It also provides a degree of foresight as to the direction the PGT practice may take in the coming years.

assisted reproductive technology↗

PubMed2026

Preimplantation genetic testing for concurrent Meckel Syndrome and hereditary breast cancer in a Chinese family harboring a novel NPHP3 pathogenic variant and a canonical BRCA2 frameshift variant.

Meckel syndrome (MKS) is a lethal autosomal recessive disease with high phenotypic and genetic heterogeneity. Defects in NPHP3 cause MKS type 7. Herein, we report a case of a Chinese family with a newborn male proband presenting with occipital encephalocele and polycystic kidneys. Whole-exome sequencing was performed on genomic DNA extracted from peripheral blood. Potential variants were assessed for pathogenicity. Two compound heterozygous variants of NPHP3 (c. 950T>C, p. Phe317Ser, and c.2694-2_2694-1delAG) were identified, which were inherited from both parents, with c.950T>C representing a novel variant. Two BRCA2 variants (c.5576_5579delTTAA, p. Ile1859Lysfs*3, and c.9357A>C,p. Leu 3119 Phe) were identified, which were inherited from the father. After the proband was diagnosed with MKS7, the couple chose preimplantation genetic testing for monogenic disorders (PGT-M) to simultaneously prevent the transmission of NPHP3 and BRCA2 pathogenic variants, leading to a successful pregnancy. Our study expands the NPHP3 variant spectrum and contributes to the molecular diagnosis and genetic counseling of MKS. This case indicates that PGT-M is a viable option for NPHP3-related MKS and BRCA-positive patients to avoid transmission while maintaining their families. Successful application of PGT-M provides a potential approach for treating other monogenic diseases.

Journal Article↗

PubMed2026

Non-invasive embryo assessment: Cell-free DNA-based genetic testing and amino acid metabolomics in relation to morphology: A case-control study.

BACKGROUND: Cell-free DNA (cfDNA) in spent culture medium (SCM) offers a non-invasive option for preimplantation genetic testing, but its low concentration and fragmentation reduce clinical reliability. Combining genetic assessment with metabolomic profiling may provide complementary information about embryo competence. OBJECTIVE: This study assessed pre-analytical cfDNA processing workflows and examined whether SCM amino acid metabolic patterns could act as practical markers of embryo quality. MATERIALS AND METHODS: In this case-control study (2021-2023), 90 embryos were evaluated using fluorescence in situ hybridization or array comparative genomic hybridization. SCM samples underwent rapid boiling, silica-based purification, or whole-genome amplification (WGA). Sex determination was performed using quantitative polymerase chain reaction (qPCR). For cfDNA quality control and aneuploidy screening, the multiplex IRFiling kit and quantitative fluorescent polymerase chain reaction (QF-PCR) were used. Amino acid profiles across embryonic developmental stages and quality grades were quantified via liquid chromatography-tandem mass spectrometry. RESULTS: Rapid boiling resulted in complete failure of DNA amplification. Conversely, silica-based purification yielded 70.0% concordance for qPCR-based sexing and 56.7% for QF-PCR. WGA achieved the highest efficacy (73.3% qPCR and 56.7% QF-PCR concordance), although quality control checks flagged occasional misclassifications. LC-MS/MS profiling revealed significantly elevated alanine and arginine levels in tripronuclear embryos. Furthermore, high-quality blastocysts exhibited elevated glutamic acid levels alongside a pronounced overall depletion of extracellular amino acids compared to low-quality counterparts and controls. CONCLUSION: WGA improves cfDNA detectability and qPCR accuracy compared with boiling or purification, but remains inadequate as a standalone screening approach. SCM amino acid profiling provides informative, complementary metabolic signatures of developmental competence, supporting a multimodal strategy for non-invasive embryo assessment.

Amino acid metabolism↗

PubMed2025

Targeted Gene Sequencing in a Male Adult Diagnosed With X-Linked Osteoporosis Due to a Novel p.(Arg398Profs*2) PLS3 Variant.

Pathogenic loss-of-function variants in the plastin-3 gene (PLS3), encoding plastin-3 protein, are associated with early-onset X-linked osteoporosis. We present the case of a young adult male patient, with a history of multiple fragility fractures and blue sclerae, who was clinically diagnosed with osteogenesis imperfecta (OI) type 1 in childhood. He has been managed with intravenous bisphosphonate therapy, leading to an increase in bone density at the spine, stable bone density at the femoral neck, and a period free of fractures while on antiresorptive therapy. Two decades later, with a focus on reproductive family planning, a novel PLS3 variant was identified on genetic testing. This case report highlights an important role for genetic testing in patients with early-onset osteoporosis or a clinical diagnosis of OI. With the emergence of new targeted therapeutics and advanced reproductive options, such as preimplantation genetic testing, obtaining an accurate molecular diagnosis is key.

PLS3↗

PubMed2024

Single-cell sequencing shows mosaic aneuploidy in most human embryos.

Mammalian preimplantation embryos often contain chromosomal defects that arose in the first divisions after fertilization and affect a subpopulation of cells - an event known as mosaic aneuploidy. In this issue of the JCI, Chavli et al. report single-cell genomic sequencing data for rigorous evaluation of the incidence and degree of mosaic aneuploidy in healthy human in vitro fertilization (IVF) embryos. Remarkably, mosaic aneuploidy occurred in at least 80% of human blastocyst-stage embryos, with often less than 20% of cells showing defects. These findings confirm that mosaic aneuploidy is prevalent in human embryos, indicating that the process is a widespread event that rarely has clinical consequences. There are major implications for preimplantation genetic testing of aneuploidy (PGT-A), a test commonly used to screen and select IVF embryos for transfer. The application and benefit of this technology is controversial, and the findings provide more cause for caution on its use.

Pregnancy↗

PubMed2026

Prevalence and mechanistic origins of genome-wide ploidy abnormalities in ICSI derived human preimplantation embryos.

BACKGROUND: Genome-wide ploidy abnormalities (GWPA) constitute a distinct and clinically significant class of chromosomal errors that arise during human preimplantation development. However, the developmental origins and prevalence of GWPA remain incomplete and poorly understood. METHODS: To evaluate the frequency and origin of GWPA in human embryos, we have retrieved preimplantation genetic testing (PGT) haplotyping data, derived from 3798 blastomere and 3593 trophectoderm biopsies. Prior haplotype reconstruction and determination of parental origin were performed using B-allele frequency-aware haplotyping (haplarithmisis). RESULTS: GWPA were detected in 113 biopsies: 81 cleavage-stage embryos and 32 blastocysts. Genome-wide loss of heterozygosity of maternal origin was the most frequent abnormality. Triploidy was the second most common aberration present in 35 embryos: 24 cleavage-stage embryos and 11 blastocysts, with the majority resulting from maternal meiosis II errors. In addition, we uncover less-characterized abnormalities, providing new insights into the chromosomal mechanisms driving early human embryonic development. CONCLUSIONS: GWPA occur in 2.16% of cleavage-stage and 0.89% of blastocyst-stage ICSI embryos, showing a strong selection against GWPA during preimplantation development. This study also demonstrates that using appropriate methods to detect GWPA when screening ICSI embryos can help prevent the transfer of nonviable embryos.

Humans↗

PubMed2024

Assessment the carrier frequency of monogenic diseases in populations requiring assisted reproductive technology.

PURPOSE: The objective of this study is to assess the carrier frequency and pathogenic variation of monogenetic diseases in a population of 114 subjects in Han Chinese from Hebei province who are undergoing assisted reproductive technology through the utilization of Expanded Carrier Screening (ECS). METHODS: The study utilized a panel consisting of 155 severe monogenic recessive genetic diseases for ECS. Next-generation sequencing technology was employed to identify specific variants associated with ECS in a cohort of 114 subjects from 97 couples, comprising 97 females and 17 male spouses. RESULTS: A total of 114 individuals received ECS. The carrier rate of pathogenic genes in the enrolled population was 44.74% (51/114). Among the 97 females, the carrier rate of pathogenic genes was higher in those without assisted reproduction indicators than in those with assisted reproduction indicators (59.09% vs. 41.33%). However, the carrier rate of pathogenic genes in males without assisted reproductive technology was slightly lower than that with assisted reproductive technology (40% vs. 41.67%). Among both female and male participants, the carrier rate of pathogenic genes between individuals without indicators of assisted reproduction and those with such indicators was 55.55% vs. 41.38%. In 51 carriers, 72.55% (37/51) carried one genetic variant, 25.49% (13/51) carried two genetic variants, and 1.96% (1/51) carried three genetic variants. A total of 38 pathogenic genes were detected in this study, and GJB2 and MMACHC were most common. The carrier rates of the two genes were both 5.26% (6/114). A total of 55 variations were detected, and c.235delC was most frequently found. The carrier rate was 3.51% (4/114). The incidence of couples carrying the same pathogenic genes was 1.03% (1/97). CONCLUSIONS: The findings elucidate the carrier rate of pathogenic genes among 155 severe monogenic recessive genetic diseases and underscore the significance of ECS as a preventive measure against congenital anomalies. When both partners carry the same genetic mutation for a monogenic disease, preventive strategies can be taken in offspring through preimplantation genetic testing (PGT), prenatal genetic testing, or the utilization of donor gametes. ECS is instrumental in assessing reproductive risk, guiding fertility-related decisions, and reducing the prevalence of monogenic recessive genetic disorders in subsequent generations.

Humans↗

PubMed2026

Clinical and functional characterization of a novel homozygous non-canonical splice mutation (c.1910-15_1910-11delinsTTACA) in CEP290 causing Joubert syndrome.

BACKGROUND: Joubert syndrome (JS) is a rare, predominantly autosomal recessive neurodevelopmental disorder characterized by hypotonia, motor delay, intellectual disability, oculomotor apraxia, and the hallmark "molar tooth sign" on axial view of MRI. JS is genetically heterogeneous, with pathogenic variants identified in more than 40 genes involved in primary cilia function. Among these, CEP290 is one of the most frequently mutated genes. RESULTS: In this study, we investigated two children-an 11-year-old boy (the proband) and his 5-year-old sister-both presenting with a similar phenotype consistent with JS. The parents, who self-identified as Chechen, reported distant consanguinity. The family also included a healthy 13-year-old daughter. The proband had previously been evaluated by a neurologist and underwent whole-genome sequencing (WGS); however, no causative variants were identified initially. After phenotype reassessment by a clinical geneticist, we performed a reanalysis of the raw WGS data and identified a novel homozygous intronic variant of uncertain significance (VUS), c.1910-15_1910-11delinsTTACA in CEP290 (NM_025114.4). Sanger sequencing confirmed that both the proband and his affected sister were homozygous for this variant, which they inherited from their heterozygous parents. Their healthy sister did not carry the variant. mRNA-sequencing and targeted cDNA sequencing (read depth ~ 100,000x) demonstrated that this intronic variant causes completely aberrant splicing of CEP290 pre-mRNA. Predominantly this variant causes the skipping of exon 20 in the main CEP290 transcript. Alternatively, the variant results in partial inclusion of intron 19 into the mRNA, elongation of exon 20 by 58 nucleotides, and a homozygous substitution chr12:88114573 (ACTGTGTA> TTACAGTA). No canonical mRNA isoform was detected when the variant was homozygous. Both the predicted severe truncation and the likely degradation of aberrant transcripts through nonsense-mediated decay (NMD) would correspond to complete loss of CEP290 function. Following the reclassification of this VUS to likely pathogenic, the family was able to pursue in vitro fertilization (IVF) with preimplantation genetic testing for monogenic disorders (PGT-M). CONCLUSION: Our study highlights the critical importance of proper phenotyping prior to referral for WES/WGS as well as of combining NGS with functional mRNA studies to achieve a molecular diagnosis for patients with predicted splice-site mutations in JS-associated genes. It also emphasizes the need for functional reassessment of VUS when genomic data are expected to guide reproductive decision-making within affected families.

Humans↗

PubMed2026

PEStimate: predicting offspring disease risk after polygenic embryo screening.

MOTIVATION: Polygenic embryo screening (PES) is a new, controversial technology, whereby human in vitro fertilization embryos are screened for their genetic risk of complex, polygenic diseases. PES aims to reduce the disease burden in offspring by prioritizing the selection of low-risk embryos. However, given that polygenic diseases are usually late-onset, PES outcomes must be estimated by epidemiological modeling. The liability threshold model has been previously used to predict outcomes. However, predictions rely on complex sets of equations, some of which require numerical integration or simulation. Further, previous models failed to account for the possibility that the selected embryo will not be born. RESULTS: Here, we present PEStimate, a freely available online app for predicting PES outcomes when screening for a single disease. PEStimate predicts the offspring risk with and without PES, as well as generates plots of the risk reduction versus key parameters. Users can adjust the number of available embryos, the live birth rate, the disease prevalence, the accuracy of the genetic risk predictor, the embryo selection method, the genetic risk of parents, and the disease status of parents, siblings, uncles/aunts, and grandparents of the embryos. Our model includes, for the first time, the possibility of embryo implantation failure, showing that risk reductions have been previously overestimated. PEStimate provides geneticists, healthcare professionals, patients, and other stakeholders with a necessary tool for examining the impact of PES and weighing its potential benefits against possible personal and societal harms. AVAILABILITY AND IMPLEMENTATION: PEStimate: https://polygenicembryo.shinyapps.io/pestimate. Source code: https://github.com/Lirazk/PEStimate.

Humans↗

PubMed2026

A Novel SLC25A4 Variant Causing Mitochondrial Dysfunction, Myopathy and Cardiomyopathy: A Functional and Molecular Characterization.

SLC25A4, solute carrier family 25 member 4, gene is a member of the mitochondrial carrier subfamily within the solute carrier protein family. Pathogenic variants in SLC25A4 are associated with a spectrum of mitochondrial disorders that exhibit variable inheritance patterns and clinical manifestations. Specifically, dominantly inherited variants are typically associated with progressive external ophthalmoplegia with mitochondrial DNA deletions, recessively inherited variants are linked to myopathy and cardiomyopathy, and de novo variants can result in early-onset fatal disease presentations. In this study, we aimed to identify and characterize the disease-causing mutation(s) in a nine-year-old female patient from a consanguineous Saudi family. The patient was asymptomatic until the age of 3 years, when she presented with cardiomyopathy and myopathy. Comprehensive genetic analysis inclusive of whole exome sequencing and segregation analysis using Sanger sequencing identified an SLC25A4 variant (NM_001151.4: exon 2: c.112-1G>C) as the most likely cause of the disease. To assess transcript-level effects, we performed RT-PCR on RNA extracted from the patient's cultured lymphoblast cell lines (LCLs) and fibroblast cell lines (FCLs). RT-PCR analysis demonstrated that the variant causes aberrant splicing, resulting in a 6 bp in-frame deletion (p.Gln37_Val38del) in the ANT1 protein. Quantitative RT-PCR demonstrated reduced SLC25A4 transcript levels in both FCLs and LCLs. Quantitative PCR analysis of mitochondrial DNA demonstrated a trend toward increased mtDNA copy number in patient-derived FCLs compared with controls, suggesting a possible compensatory response to mitochondrial dysfunction. Furthermore, Seahorse assays revealed marked reductions in both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in patient-derived FCLs compared with controls. These findings expand the molecular and functional spectrum of SLC25A4-associated disease and may inform clinical practice, including genetic interventions such as preimplantation genetic diagnosis, premarital genetic screening, targeted genetic counseling, and cascade testing of at-risk family members.

Humans↗

PubMed2025

Eugenics and polygenic embryo screening: Public, clinician, and patient perceptions of conditions versus traits.

PURPOSE: Polygenic embryo screening (PES) estimates an embryo's genetic chances of developing complex conditions (eg, cancer) and traits (eg, height). Stakeholders have raised concerns that PES promotes eugenic practices and ideology. METHODS: We surveyed a nationally representative sample of the US public on approval of screening embryos for 12 conditions and 12 traits and examined the association between disapproval and concern about eugenics. We also conducted semistructured interviews with US-based reproductive endocrinology and infertility specialists and patients undergoing in vitro fertilization on their perspectives toward PES. RESULTS: Among the US public (n = 1423), disapproval of screening embryos for traits has a stronger association with concern that PES promotes eugenics than disapproval of screening embryos for conditions. Interviews with reproductive endocrinology and infertility specialists (n = 27) and patients undergoing in vitro fertilization (n = 26) suggest that perceptions of PES as eugenic were more common when discussing screening and selecting for or against traits versus selecting against conditions. CONCLUSION: Results suggest PES for traits is more frequently associated with eugenics and perceived often as unacceptable, whereas PES for conditions is perceived sometimes as acceptable. Future research should explore whether the distinction between conditions and traits is meaningful in the definition of eugenics and/or approval of genomics-based embryo selection and how that influences clinical practices and policy.

Humans↗

PubMed1975

Infection of mouse blastocysts with SV40 DNA: normal development of the infected embryos and persistence of SV40-specific DNA sequences in the adult animals.

In SV40-transformed culture cells, viral-specific sequences have been found to be covalently linked to host sequences (Sambrook et al. 1968). The most appealing interpretation to explain the presence of SV40-specific sequences in adult mice following infection at the preimplantation stage would be to assume that the viral DNA was integrated at this early stage of development into the host genome and was thus conserved during further development. However, our results do not exclude an extrachromosomal existence of the SV40 genome, for example, as an independently replicating plasmid or as a lytic infection in a few permissive cells. So far our attempts to demonstrate autonomous SV40 DNA replication in early mouse embryos have been unsuccessful. We plan to investigate whether the SV40-specific information can be genetically transmitted from the infected mice to their offspring; chromosomal integration would be proven if transmission of SV40 DNA occurred in accordance with simple Mendelian expectations. The injection of mouse blastocysts with purified SV40 DNA did not detectably interfere with normal development of the embryos to healthy adult mice, which were still tumor-free at one year of age. This was not due to the trivial possibility that the viral DNA did not successfully infect and was eliminated from the injected embryos, as virus-specific DNA sequences were detected in 40% of the infected year-old animals, or in about 25% of DNA preparations extracted from some of their tissues (Table 1). It is nevertheless possible that the animals may not have been old enough to exhibit tumorigenesis of SV40 origin; to test this possibility, the experiment will have to be repeated for longer survival periods. The absence of any obvious signs of expression of viral genetic functions, i.e., tumor formation, up to one year of age of the host is reminiscent of the "cryptic transformants" described earlier (Smith et al. 1972) which harbor SV40 information but behave essentially like normal untransformed cells. Whether transcription or translation of the virus gene can occur in infected mice is presently an open question. Testing for expression of an integrated viral genome in diverse differentiated tissues may provide a useful model system to study the regulation of differentiation. These matters are currently being investigated.

Animals↗

PubMed1979

On the mutagenicity of methadone hydrochloride. Induced dominant lethal mutation and spermatocyte chromosomal aberrations in treated males.

The mutagenicity of methadone hydrochloride was tested in male mice using the dominant lethal mutation technique and the spermatocyte test of treated mice. Male mice of C3H inbred strain received one of the following doses, 1, 2, 4 or 6 mg/kg body weight once a day for 3 consecutive days. Another group of mice served as control and received saline instead. Treated males were then mated to virgin females at 3-day intervals for a period of 45 days. Pregnant females were dissected at mid-term and the corpora lutea and intrauterine contents were recorded. The spermatocytes of treated males were examined 45-50 d after treatments with methadone and abnormal pairing configurations were scored. The methadone treatment was found to increase the rate of preimplantation deaths consistently in all post-meiotic stages with all doses used. In addition, the higher doses, 4 and 6 mg, affected spermatogonia stages. Quantitatively, the dose-response relationship cannot be demonstrated though the spectrum of effect increased with higher doses as more spermatogenesis stages became more sensitive to the treatment. In many cases the frequency of live implants showed a positive correlation with preimplantation deaths in contrast with the frequency of early deaths which showed only sporadic variation. The mutation indices based on total embryonic death indicate that methadone hydrochloride affected several stages of germ-cell maturation namely, spermatozoa (M.I. 14-35), late spermatids (M.I. 15-48), early spermatids (M.I. 14-50), late spermatocytes (M.I. 15-43) and spermatogonial stages (M.I. 12-63). Chromosome analysis at diakinesis-metaphase 1 revealed significant increase in the frequency of sex chromosome and autosome univalents with different doses of methadone. The smallest dose applied was quite effective and the data represent direct dose-response relationship. Of the multivalent configuration, the most frequent type was chain quadrivalents. The frequencies of total translocations per cell were estimated as 0.1, 0.16 and 0.2 for the 4 applied doses illustrating a dose-response relationship for the doses: 1, 2 and 4 mg, whereas with the higher dose, 6 mg, an abrupt decrease was apparent (0.05). This study calls for concern regarding the possible genetic hazards this drug may impose upon human populations.

Animals↗