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PubMed2026

Height variation independent of known genetic variants and health in later life: a cohort study.

BACKGROUND: Adult-attained height is associated with later-life health, but it reflects both genetic and nongenetic influences. The health implications of height variation not explained by known common height-associated genetic variants remain unclear. OBJECTIVES: This study aimed to examine associations of residual height (height variation independent of known genetic variants) with multiple disease incidence and all-cause mortality in later life. METHODS: In this cohort study of 407,366 adults of European ancestry (aged 40-70 y) in the United Kingdom Biobank (2006-2010), sex- and age-specific genetically predicted height was estimated from 9863 height-associated variants, adjusted for 30 principal components of ancestry. Residual height was calculated as the difference between observed and genetically predicted height. Plasma proteomics (2054 proteins; Olink Explore) were profiled. Deaths and 49 incident diseases were ascertained through national registries. Multivariable Cox models estimated associations of residual height and related proteins with disease incidence and mortality. RESULTS: Higher residual height [mean (standard deviation, SD), 0.0 (4.8)] was associated with more favorable self-reported preadulthood exposures (e.g., later birth years, no maternal smoking around birth, being breastfed as an infant, no adoption experience, and lower childhood adversity scores) and lower hazard ratios (HRs) of 32 out of 49 diseases (median follow-up = ∼12.5 y). Using participants with residual height within ±0.5 SDs from the mean as reference, those with residual height < -2 SDs had higher adjusted HRs of mortality [1.61; 95% confidence interval (CI): 1.50, 1.72], multimorbidity (1.28; 95% CI: 1.12, 1.46), cardiovascular disease (1.45; 95% CI: 1.32, 1.60), psychiatric/neurological disease (1.38; 95% CI: 1.28, 1.48), and other disease categories (e.g., diabetes, digestive, and musculoskeletal diseases). In contrast, higher genetically predicted height was associated with a higher incidence of 19 diseases, including subtypes of cancer, non-atherosclerotic cardiovascular diseases, and musculoskeletal diseases, as well as higher all-cause mortality. We identified 806 plasma proteins related to inflammation, immune response, and autophagy via tumor necrosis factor, Nuclear factor-kappa B, phosphoinositide-3 kinase/protein kinase B, and Janus kinase/signal transducer and activator of transcription signaling pathways, which were associated with residual height and multiple diseases and mortality. CONCLUSIONS: Higher residual height is associated with lower disease incidence and mortality, with associations that are distinct from those for genetically predicted height.

Humans↗

PubMed2026

Clinical and endocrine correlates of genetic etiologies in severe hypospadias: Study from 34 patients.

OBJECTIVE: Hypospadias is a prevalent congenital anomaly (0.3%-1.0%); however, severe hypospadias (defined as proximal cases with the meatus at the penoscrotal junction, scrotum, or perineum) is a rare and clinically challenging entity with a multifactorial etiology. This study aimed to characterize the interrelationships among the clinical, endocrine, and genetic profiles in children with severe hypospadias. MATERIALS AND METHODS: We conducted a comprehensive analysis of 34 male patients with severe hypospadias. Preoperative hormone levels were measured using two methods: chemiluminescent immunoassay for luteinizing hormone and follicle-stimulating hormone, and liquid chromatography-tandem mass spectrometry for testosterone (T), dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), 17α-hydroxyprogesterone (17α-OHP), and other steroids. Genetic analysis was conducted via whole exome sequencing. RESULTS: The diagnostic yield of clinically relevant genetic variants (including pathogenic and likely pathogenic, and variants of uncertain significance) in our cohort was 41.2% (14/34) of patients. Patients carrying these variants exhibited a more complex phenotypic profile compared to non-carriers, including a significantly higher rate of patients with ≥3 associated malformations and a greater prevalence of cryptorchidism. Furthermore, the group with clinically relevant variants showed selective elevations in adrenal-derived precursors, specifically 17α-OHP and DHEA. Correlation analysis revealed significant positive associations of both 17α-OHP levels and the T/DHT ratio with the number of associated malformations. CONCLUSION: This study reveals significant genetic heterogeneity in patients with severe hypospadias. Those carrying genetic variants was associated with more severe clinical phenotypes, while certain endocrine variations, including the elevation of adrenal-derived hormones, were also observed in this cohort.

Humans↗

PubMed2026

Genetic Ancestry and Carrier Variant Frequency Enrichment in a Colombian Andean Population: Insights From the Eje Cafetero.

Colombia is one of the most genetically diverse populations in Latin America, and its demographic process has promoted the persistence and local enrichment of deleterious alleles, increasing the frequency of autosomal recessive disorders, particularly in semi-isolated Andean populations such as the Eje Cafetero. However, exome-based reference data from this region remain scarce, limiting ancestry-aware variant interpretation and carrier screening strategies. We aimed to characterize the ancestry proportions of this population using exome data, and to estimate the carrier frequency and distribution of pathogenic and likely pathogenic (P/LP) variants in clinically relevant recessive genes. We conducted a cross-sectional study with whole-exome sequencing (WES) in 316 unrelated individuals from the Colombian Eje Cafetero. P/LP variants were evaluated in 454 genes associated with autosomal recessive disorders. The global ancestry proportions were estimated using a validated panel of 250 exome-compatible ancestry-informative markers. Carrier frequencies were compared against Non-Finnish Europeans (NFE) and Admixed Americans (AMX) from gnomAD v4. The cohort showed predominant European ancestry (mean 51%), followed by Native American (36%) and African (13%) components. We identified 151 carriers of 89 distinct pathogenic variants across autosomal recessive genes. The most frequent variants were SERPINA1 c.863A>T (5.5%), CFTR c.1210-11T>G (3.5%), and PYGM c.1094C>T (1.5%). Also, recurrent variants were significantly enriched compared with both NFE and AMX populations, supporting regional founder effects. This study represents one of the most comprehensive exome-based genetic characterizations of the Colombian Eje Cafetero, revealing ancestry-specific enrichment of clinically relevant autosomal recessive variants driven by founder effects.

Female↗

PubMed2026

Genetic Diversity of BK Polyomavirus Among Renal Transplant Recipients in Yunnan, China.

BK polyomavirus (BKV) infection, a common complication following kidney transplantation, can lead to BKV-associated nephropathy (BKVN). Molecular genetic studies have classified BKV into four genotypes (I-IV); however, comprehensive molecular characterization of BKV strains circulating in China remains limited. This study aimed to elucidate the predominant subtypes and clinical infection characteristics of BKV strains among kidney transplant recipients in Yunnan, a province in southwestern China. PCR-amplified BKV DNA sequences from kidney transplant recipients were aligned with reference strains and subjected to phylogenetic analysis. The viral VP1 gene was successfully amplified from 180 participants, spanning 16 ethnic groups. Genotype I was the predominant viral strain (56.66%, 102/180), followed by genotype IV (43.33%, 78/180), while genotypes II and III were not detected. Among genotypic subtypes, IVc-1 was most prevalent (40.0%, 72/180), followed by Ic (38.3%, 69/180) and Ib-1 (18.3%, 33/180). IVa-1 and IVa-2 were rare, identified in only 0.6% (n = 1) and 2.2% (n = 4) of cases, respectively. No significant differences in sex, age, BKVN incidence, BK viremia, or viruria were observed between patients with BKV-I and BKV-IV infections. Among the five confirmed BKVN cases, two were genotyped as subtype Ic, one as Ib-1, and two as IVc-1. Clinical phenotypes were also comparable between patients with BKV-I and BKV-IV infections. This study represents the largest single-center sequencing analysis of BKV in kidney transplant recipients in China, offering a valuable genomic resource for future research.

Humans↗

PubMed2026

Flux rewiring enables native D-glucosamine production in Escherichia coli.

D-Glucosamine is an industrially important amino sugar used in pharmaceuticals, nutraceuticals, and functional materials, yet its production remains dominated by chemical extraction from chitinous biomass, raising sustainability and allergen concerns. Escherichia coli natively synthesizes D-glucosamine directly from D-glucose through endogenous metabolism, revealing an underutilized amino sugar biosynthetic capability. Building on this native pathway, D-glucosamine production was enhanced through targeted genetic modifications and systematic optimization of nitrogen metabolism and cultivation conditions, reaching 9.2 g L-1 under shake-flask conditions. This work extends a phosphorylation-dephosphorylation strategy previously developed for neutral rare sugars to amino sugar biosynthesis, demonstrating the broader applicability of this metabolic design principle. Phosphatase identity emerged as a key control point for product formation: YbiV was the most effective phosphatase for selective D-glucosamine production, whereas alternative phosphatases redirected flux toward D-sedoheptulose. This enzyme-dependent flux partitioning further enabled tunable co-production of D-glucosamine and D-sedoheptulose. Native amino sugar biosynthesis in E. coli provides a controllable framework for producing chemically distinct sugars through endogenous metabolism and establishes a generalizable strategy for engineering amino sugar and other nitrogen-containing metabolite biosynthesis.

Escherichia coli↗

PubMed2026

Analysis of deep learning techniques in computer-aided diagnosis for meniscus injuries: a systematic literature review.

Meniscus informatics is a growing subject of study in the healthcare industry. One of the major hindrances to the healthcare system's transformation is obtaining knowledge and meaningful information from complicated, high-dimensional and diverse sources. Modern biomedical research, for instance, has seen an increase in the use of complex, dissimilar, poorly documented, and generally unstructured electronic health records, imaging, sensor data and text, even after many current techniques have been used to extract more robust and useful elements from the data for analysis. New efficient standards for building end-to-end learning models from complex data are therefore needed. Therefore, the current study aims to examine the most recent research on the use of deep learning techniques for diagnosing meniscus tears and recommend creating comprehensive and meaningful interpretable structures that might benefit the healthcare industry. We also draw attention to shortcomings and the need for better technique development, and we provide new perspectives about this exciting new development in the field.

Humans↗

PubMed2026

CNNM2 in schizophrenia: multilevel evidence of genetic susceptibility, magnesium homeostasis, neurodevelopment and cognitive dysfunction.

Schizophrenia (SCZ) is a common psychiatric disorder with a complex, genetically and environmentally influenced etiology, but the specific pathogenesis remains unclear. In recent years, the SCZ susceptibility gene CNNM2 (encoding cyclin M2) located at the 10q24.32-33 locus has received widespread attention. The well-validated SCZ risk interval 10q24.32-33 harbors two independent risk variants: rs11191580 in NT5C2 (significantly associated with CNNM2 mRNA and protein levels) and rs7914558 in CNNM2. Results from functional genomic analyses indicate that lower CNNM2 expression is significantly associated with SCZ. Imaging genetics studies have demonstrated that carriers of risk alleles of CNNM2 SNPs exhibit alterations in brain structure. Animal model studies have revealed that Cnnm2 downregulation in mice leads to impairments in sensorimotor gating and cognitive function. As an Mg2+ transporter, CNNM2 primarily maintains systemic Mg2+ homeostasis. According to clinical studies, a proportion of patients with SCZ exhibit reduced Mg2+ concentrations in plasma and cerebrospinal fluid. CNNM2 dysfunction may contribute to the pathology of SCZ by disrupting Mg2+ homeostasis, thereby affecting neurodevelopment and synaptic plasticity. A systematic consolidation of current evidence supporting the involvement of CNNM2 in SCZ pathogenesis provides a direction for further investigation of the pathological mechanisms underlying this disease, and for identification of novel targets for clinical intervention..

Schizophrenia↗

PubMed2026

Transcription regulation of cell fate plasticity - from embryonic development to tissue regeneration.

Cell fate plasticity refers to the capacity of cells sharing the same genome to alter, reverse, or reconfigure their identity under physiological, pathological, or experimental conditions. This property underlies embryonic development, cellular reprogramming, and tissue regeneration, but becomes progressively restricted as lineage identity is stabilized. Embryonic development represents an intrinsic process of fate transitions, whereas reprogramming and regeneration reveal how differentiated cells can dedifferentiate or transdifferentiate under specific conditions. Across these contexts, plasticity is governed by multilayered regulatory networks involving transcription factors, epigenetic regulators, cofactors, and the core transcription machinery. Robust regulatory programs stabilize cell identity, whereas stochastic fluctuations in gene expression and chromatin state can prime cells for fate transitions, adding a tunable dimension to plasticity control. In this review, we synthesize recent advances in the regulation of cell fate plasticity across development, reprogramming, and regeneration, highlighting how transcription factors, epigenetic modifications, transcriptional cofactors, and core transcription machinery cooperate to control cell fate decisions and plasticity.

Animals↗

PubMed2026

Statistical test to compare the linkage model and the admixture model based on central limit results.

In the Admixture Model, the probability that an individual carries a certain allele at a specific marker depends on the allele frequencies in K ancestral populations and the proportion of the individual's genome originating from these populations. The markers are assumed to be independent. The Linkage Model is a Hidden Markov Model that extends the Admixture Model by incorporating linkage between neighboring loci. We prove consistency and asymptotic normality of maximum likelihood estimators for the ancestry of individuals in the Linkage Model, complementing earlier results by (Pfaff et al., 2004; Pfaffelhuber and Rohde, 2022; Heinzel, 2025) for the Admixture Model. These results are used to prove that a statistical test that allows for model selection between the Admixture Model and the Linkage Model is an asymptotic level-α-test. Finally, we demonstrate the practical relevance of our results by applying the test to real-world data from The 1000 Genomes Project Consortium (2015).

Genetic Linkage↗

PubMed2026

Genomic insights into end-use grain quality and nutritional traits of an ancient Indian dwarf wheat ( Triticum sphaerococcum Percival) population using a multi-locus genome-wide association study.

BACKGROUND: Triticum sphaerococcum, an ancient hexaploid wheat species, is renowned for its stress resilience and superior nutritional quality. A panel of 116 T. sphaerococcum accessions (the largest known collection at a single site globally), with six bread wheat released varieties, was evaluated for its potential for genetic quality improvement. Field experiments were conducted under standard, heat and moisture-deficit conditions across two cropping seasons for ten grain end-use quality and nutritional traits. RESULTS: Genotypes showed highly significant differences (P ≤ 0.001) for measured traits, with high broad-sense heritability resulting from substantial genotypic variance contributions. Triticum sphaerococcum consistently outperformed T. aestivum across environments, with moisture-deficit stress proving more detrimental to quality parameters than heat stress, while micronutrient content increased under stressed conditions. Trait correlations revealed that the gluten index (GI) correlated negatively with the grain hardness index (GHI), wet gluten (WG), and water-binding capacity (WB), while positively correlating with dry gluten (DG) and protein content (PRO), whereas grain iron (GFE), zinc (GZN), and protein showed consistent positive interrelationships. Two superior accessions, PAUTS10 (WG 35.13%, DG 13.71%, PRO 16.42%, GZN 50.89 ppm) and Sonamoti (WG 33.33%, DG 12.92%, PRO 16.27%, GZN 56.03 ppm), were identified, surpassing the best check variety HD3226 for quality and nutritional parameters. Multi-locus genome-wide association studies identified 30 stable quantitative trait nucleotides across environments, with candidate gene analysis revealing genes involved in transcription regulation, biosynthetic processes, metal ion homeostasis, and transport. CONCLUSIONS: Triticum sphaerococcum demonstrated superior grain quality and micronutrient potential compared with modern wheat, highlighting its value as a genetic resource for biofortification. The identification of elite accessions and stable quantitative trait nucleotides (QTNs) provides useful targets for breeding programs aimed at improving protein and micronutrient content. Integrating ancient germplasm with modern genomic tools can accelerate the development of nutritionally enhanced wheat varieties. © 2026 Society of Chemical Industry.

Triticum↗

PubMed2026

Unravelling Ovarian Cancer: an analysis of the Influence of LRP1 and PAI1 Genetic Variations.

To assess the potential association between LRP1 (rs715948) and PAI1 (rs2227631, rs1799889) gene variation and ovarian cancer (OC) susceptibility. This study evaluated the genotypic and allelic distributions of LRP1 gene and PAI1 gene variants using Restriction Fragment Length Polymorphism (RFLP) analysis in 134 °C patients and 134 healthy controls. LRP1 (rs715948) showed a significant association with OC risk. The TC genotype was (OR = 3.7823, 95% CI: 2.1732-6.5825, p < 0.0001), and the CC genotype has (OR = 2.1613, 95% CI: 1.0054-4.6459, p = 0.0484). The C allele was significantly more frequent in cases (46%) than controls (32%) (OR = 1.7684, 95% CI: 1.2443-2.5133, p = 0.0015). For PAI1 (rs2227631), AG and GG genotypes showed no significant association (p = 0.3519 and p = 0.1165, respectively). PAI1 (rs1799889) AG genotype was (OR = 5.855, 95% CI: 2.4663-13.9027, p < 0.0001), while GG genotype showed no significance (p = 0.1025). The dominant model of LRP1, (TC + CC) and C alleles, were significantly more frequent in OC cases, indicating a potential risk factor. In contrast, the dominant models (AG + GG) and G alleles of PAI1 (rs2227631, rs1799889) showed no significance with OC susceptibility. Genetic variation in LRP1 (rs715948) significantly associated with increased OC risk, particularly the TC and CC genotypes and C allele. The C allele of this gene is key markers linked to higher OC susceptibility. Whereas in PAI1 (rs2227631, rs1799889), dominant models (AG + GG) show no significance, association suggesting a less prominent role in OC susceptibility. These findings highlight LRP1 as a potential genetic biomarker for OC risk assessment, while the role of PAI1 variants warrants further investigation in larger sample size.

Humans↗

PubMed2026

Association of ERBB4 and SHBG gene polymorphisms with polycystic ovarian syndrome in South Indian women: a case-control genetic analysis.

INTRODUCTION: Polycystic ovary syndrome (PCOS) is a multifactorial endocrinological disorder with a substantial genetic component. However, the role of genes involved in follicular development and androgen regulation remains incompletely understood, particularly in South Indian populations. This study aimed to evaluate how variations in the ERBB4 and SHBG genes affect PCOS risk. METHODOLOGY: A hospital-based case-control study was conducted among 400 South Indian women, comprising 200 women with PCOS and 200 age-matched healthy controls. Genomic DNA was extracted to study SNPs at ERBB4 (rs2178575 and rs1351592) and SHBG (rs1799941 and rs727428) using ARMS-PCR genotyping. The study compared genotype and allele frequencies between cases and controls while assessing their associations with allelic, homozygous, heterozygous, dominant, recessive, and over-dominant genetic models. Genotyping accuracy was confirmed by re-genotyping and Sanger sequencing of a subset of samples. RESULTS: The ERBB4 rs2178575 polymorphism demonstrated a significant association with PCOS, as the AA genotype and A allele combination increased risk across all three genetic models, including homozygous, recessive, and allelic models. The ERBB4 rs1351592 variant was associated with 3-fold higher risk of PCOS in heterozygous and GC carriers. The SHBG rs1799941 polymorphism showed a significant link to PCOS through its effects on heterozygous and allelic states, whereas rs727428 displayed no significant connection due to its monomorphic distribution. CONCLUSION: These findings suggest that polymorphisms in ERBB4 and SHBG may contribute to PCOS susceptibility in South Indian women in a locus- and model-specific manner, revealing the intricate genetic structure that defines this medical condition.

Humans↗

PubMed2026

Genome-wide SNP data support species boundaries in sympatric Polylepis Ruiz & Pav. (Rosaceae) species from Bolivia and Ecuador.

Species delimitation in the South American genus Polylepis is notoriously challenging due to high morphological similarity and phenotypic plasticity, likely driven by hybridization and gene flow. Previous phylogenetic studies suggested that genetic structure aligns more strongly with geography than with taxonomy, questioning existing species concepts and hampering conservation efforts. We used double-digest RAD sequencing (ddRADseq) to generate genome-wide SNP data for 11 Polylepis species sampled across multiple localities in Bolivia and Ecuador. Population genetic analyses, phylogenetic inference, and network approaches were combined to assess whether genetic structure aligns more closely with taxonomy or geography. Morphologically defined species formed largely cohesive genetic lineages across regions, with species identity explaining substantially more genetic variation than locality. While localized admixture and reticulation were detected among closely related taxa, widespread species showed strong genetic cohesion and clear separation from congeners. Our results indicate that the sampled Polylepis species from Bolivia and Ecuador maintain distinct genetic identities despite localized signals consistent with gene flow. This genome-wide support for current taxonomy highlights Polylepis as a valuable model for studying speciation under gene flow and indicates that multiple geographic sampling will be essential in reconstructing a robust phylogeny of the genus, with important implications for conservation planning in Andean montane forests.

Bolivia↗

PubMed2026

Genetic diversity and recombination of NA-PRRSV field strains in Vietnam: Implications for vaccine efficacy.

Porcine reproductive and respiratory syndrome (PRRS) causes severe reproductive losses in pregnant sows and piglets, resulting in substantial economic impact on the swine industry worldwide. However, due to the significant genetic diversity and rapid evolutionary changes of the pathogen, continuous surveillance and detailed genetic analysis of circulating strains are essential. The current study aimed to evaluate the genetic diversity of the hypervariable (HV) region of non-structural protein 2 (nsp2) among North American PRRSV strains isolated from swine farms in Vietnam. Phylogenetic analysis and multiple sequence alignment were conducted to determine subtype classification and assess genetic variability. A total of 48 field isolates were obtained, of which 12.5% belonged to classical NA-PRRSV, 16.6% to NADC30-like and 70.9% to HP-PRRSV, primarily distributed across sublineages 1.4, 5.1, 8.7 and 8.9. Amino acid comparisons found multiple insertions, deletions and substitutions at various positions within the hypervariable region of nsp2. The study revealed substantial genetic variation in the HV region of nsp2 among NA-PRRSV field strains, largely associated with recombination and immune escape. These findings highlight epidemiological risks to vaccine efficacy and underscore the need for continuous molecular surveillance to support effective PRRSV control in Vietnam.

PRRSV↗

PubMed2026

[Analysis of clinical phenotypes and pathogenicity of a c.4476+5G>T variant of SCN1A gene in a Chinese pedigree affected with Genetic epilepsy with febrile seizures plus].

OBJECTIVE: To explore the pathogenicity and characteristics of a heterozygous splicing variant of SCN1A gene in a Chinese pedigree affected with Genetic epilepsy with febrile seizures plus (GEFS+). METHODS: A retrospective analysis was carried out on the clinical data and results of genetic testing of a GEFS+ pedigree consisting of 5 members who had visited the First Affiliated Hospital of Zhengzhou University on July 1, 2024. Pathogenicity of the splicing variant of the SCN1A gene was validated with a minigene splicing assay. This study was approved by the Medical Ethics Committee of the the First Affiliated Hospital of Zhengzhou University (Ethics No.: KS-2018-KY-36). RESULTS: The proband, a 24-year-old female, presented with FS in conjunct with focal seizures, and both of her younger brothers had Dravet syndrome. All of the three patients had carried a c.4476+5G>T variant of the SCN1A gene, which was unreported previously. Minigene experiment verified that the variant could cause loss of the first 7 bps of exon 24 and 138 bps from exon 23 of the SCN1A gene, resulting in alteration p.V1447_1495delfs*6 and affecting splicing. Based on the guidelines from American College of Medical Genetics and Genomics (ACMG), the variant was predicted as likely pathogenic (PVS1+PM2_Supporting). CONCLUSION: The c.4476+5G>T variant at an intronic site of the SCN1A gene probably underlay the pathogenesis of GEFS+ in this pedigree.

Adult↗

PubMed2026

Mitochondrial DNA diversity in Ecuadorian populations: Recurrence of variant 16136 within haplogroup B2.

The identification of lineage-defining variants, frequently found in the coding region of mitochondrial DNA (mtDNA), is essential for refining haplogroup classification. Most mtDNA studies in South American populations have focused on the control region (CR), which has provided important insights into population structure and maternal lineage origins, although information needed for more robust phylogenetic resolution has been neglected. This study investigates the maternal genetic structure of Ecuadorian populations by combining CR and whole mitogenome analyses. Sequences from the mtDNA CR were obtained from 461 individuals (253 Mestizos and 208 Native Americans), while complete mitogenomes were sequenced for 127 individuals to improve phylogenetic resolution by identifying lineage-defining variants present in coding region. Most mtDNA haplogroups in the two population groups analyzed were of Native American origin (A2, B2, B4, C1, D1, D4), with significant differences in the distribution of specific lineages between them. Among Mestizos, African haplogroups (all within the L branches) and Eurasian haplogroups (H, K, R, U) were detected at low frequencies, whereas no African lineages were observed among Native Americans. The results obtained highlighted a heterogeneity within Ecuadorian populations that must be considered when developing mtDNA haplotype databases for forensic purposes. Whole mitogenome sequences enabled the identification of variants that refined haplogroup classifications, provided a more accurate reconstruction of the maternal genetic diversity, and improve the discrimination between Native American and Asian maternal lineages within haplogroup B4b.

Humans↗

PubMed2026

Integrated exome and mitochondrial genome sequencing reveals the genetic landscape of primary mitochondrial diseases: findings from a large Tunisian cohort.

Primary mitochondrial diseases are a heterogeneous group of neurometabolic disorders recognized as the most common metabolic genetic diseases. They manifest at any age, affecting any tissue or organ, especially those with high energy demands, and are caused by pathogenic variants in both mitochondrial and nuclear genomes. Here, we aimed to describe the genetic spectrum of a Tunisian pediatric cohort with suspected mitochondrial diseases. We recruited 47 unrelated families who underwent exome sequencing as a first-tier test followed by whole mitochondrial genome sequencing for unsolved cases. Dedicated bioinformatic pipelines and prediction tools were used to determine the potential disease-causing variants. Sanger sequencing confirmed the presence and segregation within parents. For the newly identified variants, structural modeling was conducted to study the impact of these variants on protein structure and motions. Dual genome sequencing yielded a molecular diagnosis in 33/47 families (70%) and 18/47 (38%) showed disease-causing variants in genes encoding mitochondrial proteins. Among them, four families disclosed novel variants in FASTKD2, SERAC1 and GATB, which were supported by in-depth in silico and structural analyses demonstrating their deleterious effect. The remaining families (32%, 15/47) disclosed other metabolic and neurological disorders. An exome-first strategy delivers a high diagnostic yield in Tunisia, where consanguinity remains high and simultaneously captures mitochondrial and non-mitochondrial etiologies. Mitochondrial sequencing remains indispensable in the case of an inconclusive exome. Thus, our data expand the clinical and genetic spectrum of primary mitochondrial diseases in Tunisia, an underrepresented and admixed population.

Humans↗

PubMed2026

Origins and timing of somatic variants in the brain.

Somatic variants accumulate in human brain cells throughout the lifespan. Variant allele fraction has traditionally been used as a proxy for both the developmental timing of somatic variants and their functional effect, based on the assumption that earlier mutations are shared by larger cell populations and therefore have greater potential for severe phenotypes. However, recent discoveries challenge this simplified model. Variables such as developmental bottlenecks, lineage restriction, and cellular and molecular context play critical roles in shaping the distribution and functional impact of somatic variants in the brain. These insights support a shift toward a context-dependent framework for interpreting somatic mosaicism.

Humans↗