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Peptidoglycan recognition proteins: on and off switches for innate immunity.

Insects rely on innate immune mechanisms to defend themselves against microbes. The inducible anti-microbial peptides constitute an important arm of this defense. In Drosophila, the Toll and the Imd pathways are the major routes to induce the peptides, and it has become clear that to a certain extent, these pathways can discriminate between different microbes and mount an appropriate response to eliminate the intruder. This review discusses the proteins responsible for this discriminatory recognition, the peptidoglycan recognition proteins (PGRPs). The serum protein PGRP-SA triggers a humoral cascade of proteases upon infection by certain gram-positive bacteria to activate the Toll pathway. The membrane-bound receptor PGRP-LC activates the Imd pathway in response to certain gram-negative bacteria or their peptidoglycans. Other PGRPs have enzymatic activity, cleaving lactylamide bonds in peptidoglycan to eliminate its immunogenicity, thus turning off the immune response. The PGRP family is conserved from insects to man. Short mammalian PGRP variants are synthesized in neutrophils and stored in granules. These PGRPs seem to influence the survival of phagocytosed non-pathogenic bacteria. Long PGRP variants are expressed in the liver and secreted into the bloodstream where their peptidoglycan-degrading activity might serve scavenger functions.

Amino Acid Sequence↗

Functional significance and clinical phenotype of nontruncating mismatch repair variants of MLH1.

BACKGROUND & AIMS: Germline mutations in mismatch repair genes are associated with hereditary nonpolyposis colorectal cancer. A significant proportion of mutations are nontruncating and associated with a variability of clinical phenotype and microsatellite instability and with occasional presence of residual protein in tumor tissue that suggests impaired functional activity but not total lack of mismatch repair. To address pathogenic significance and mechanism of pathogenicity, we studied the functionality of 31 nontruncating MLH1 mutations found in clinically characterized colorectal cancer families and 3 other variations listed in a mutation database. METHODS: Mutations constructed by site-directed mutagenesis were studied for protein expression/stability, subcellular localization, protein-protein interaction, and repair efficiency. The genetic and biochemical data were correlated with clinical data. Finally, comparative sequence analysis was performed to assess the value of sequence homology as a tool for predicting functional results. RESULTS: Altogether, 22 mutations were pathogenic in more than one assay, 2 variants were impaired in one assay, and 10 variants acted like wild-type protein. Twenty of 34 mutations affected the quantity of MLH1 protein, whereas only 15 mainly amino-terminal mutations were defective in an in vitro repair assay. Comparative sequence analysis correctly predicted functional studies for 82% of variants. CONCLUSIONS: Pathogenic nontruncating alterations in MLH1 may interfere with different biochemical mechanisms but generally more than one. The severe biochemical defects are mirrored by phenotypic characteristics such as early age at onset and high microsatellite instability, whereas variants with no or mild defects in functionality are associated with variable clinical phenotypes.

Adaptor Proteins, Signal Transducing↗

E-cadherin gene variants in gastric cancer families whose probands are diagnosed with diffuse gastric cancer.

To identify germline E-cadherin mutations responsible for the predisposition to diffuse gastric cancer (DGC) among the Japanese, we screened 17 patients with familial aggregation of gastric cancer by sequencing analysis. All the patients were diagnosed with DGC and had at least 1 sibling with gastric cancer. Two novel E-cadherin gene variants were detected. One was detected in 1 patient only and associated with an amino acid substitution (Val/Met) at codon 832 in the region essential for binding to beta-catenin. The M832 variant was detected not only in the proband but also in 2 other gastric cancer patients in the family. Immunohistochemical analysis of gastric cancer tissue from the proband revealed that E-cadherin expression was markedly reduced and beta-catenin expression was also reduced in cancer cells. However, no significant difference in the activity of beta-catenin binding was detected between the M832 variant and V832 wild-type E-cadherin in immunofluorescence and immunoprecipitation/Western blot analyses. The other was detected in 5 patients and was located in the splice donor site (IVS1+6T/C); however, RT-PCR analysis indicated that the IVS+6C variant did not cause an aberrant splicing. Thus, the M832 variant could be a germline mutation causative of familial aggregation of DGC, although further functional studies are needed to understand the pathogenic significance of this variant.

Adult↗

Emerging genes implicated in human congenital heart disease: a 2023-2025 scoping review.

BACKGROUND: Congenital heart disease (CHD) is the most common major congenital anomaly and a leading cause of infant morbidity and mortality. The rapid expansion of genomic technologies has accelerated the discovery of rare genetic variants implicated in CHD pathogenesis. However, most individuals with CHD still lack an identifiable molecular etiology. The purpose of this scoping review is to systematically characterize genes reported in the recent literature as candidate CHD-associated genes and contextualize these findings within the stages of cardiac morphogenesis. METHODS: PubMed was searched using predefined terms related to CHD and genetic variants, supplemented by a prospectively maintained internal database. We included human studies published between January 2023 and December 2025 that identified pathogenic, likely pathogenic, or uncertain monogenic variants in at least one patient with CHD. Animal-only studies, chromosomal abnormalities, copy number variants, multigenic associations, transcriptomic/proteomic analyses, reviews, and maternal-only genetic studies were excluded. Gene-disease validity classifications were assigned using the Clinical Genome Resource (ClinGen) CHD Gene Curation Expert Panel framework. RESULTS: Of 2,834 screened articles, 391 studies met inclusion criteria, identifying 912 unique genes reported as candidate CHD-associated genes. Frequently reported genes included PTPN11, NOTCH1, GATA4, JAG1, MYH6, GATA6, and LZTR1. Identified genes spanned all major stages of cardiogenesis, including developmental priming, cardiac progenitor specification, left-right axis formation, neural crest migration, outflow tract development, septation, and postnatal structural remodeling. Studies increasingly implicated ciliary dysfunction, transcriptional regulation, ribosomal biology, and multigenic inheritance in CHD pathogenesis. Emerging methodologies included stem cell-derived cardiac models, machine learning-based gene prioritization, and epigenetic analyses. CONCLUSIONS: Recent literature substantially expands the catalog of candidate genes that may be associated with CHD and highlights the biologic complexity underlying cardiac morphogenesis. Integration of genomic, developmental, and functional approaches will be essential to improve mechanistic understanding, refine genetic counseling, and support future precision medicine strategies for CHD.

Cardiac development↗

The broad host range pathogen Pseudomonas aeruginosa strain PA14 carries two pathogenicity islands harboring plant and animal virulence genes.

The ubiquitous bacterium Pseudomonas aeruginosa is the quintessential opportunistic pathogen. Certain isolates infect a broad range of host organisms, from plants to humans. The pathogenic promiscuity of particular variants may reflect an increased virulence gene repertoire beyond the core P. aeruginosa genome. We have identified and characterized two P. aeruginosa pathogenicity islands (PAPI-1 and PAPI-2) in the genome of PA14, a highly virulent clinical isolate. The 108-kb PAPI-1 and 11-kb PAPI-2, which are absent from the less virulent reference strain PAO1, exhibit highly modular structures, revealing their complex derivations from a wide array of bacterial species and mobile elements. Most of the genes within these islands that are homologous to known genes occur in other human and plant bacterial pathogens. For example, PAPI-1 carries a complete gene cluster predicted to encode a type IV group B pilus, a well known adhesin absent from strain PAO1. However, >80% of the PAPI-1 DNA sequence is unique, and 75 of its 115 predicted ORF products are unrelated to any known proteins or functional domains. Significantly, many PAPI-1 ORFs also occur in several P. aeruginosa cystic fibrosis isolates. Twenty-three PAPI ORFs were mutated, and 19 were found to be necessary for full plant or animal virulence, with 11 required for both. The large set of "extra" virulence functions encoded by both PAPIs may contribute to the increased promiscuity of highly virulent P. aeruginosa strains, by directing additional pathogenic functions.

Animals↗

A poxvirus antigen associated with pathogenicity for rabbits.

White pock variants of cowpox virus give papular lesions on intradermal inoculation of rabbits, without the necrosis and haemorrhage that are produced by wild type cowpox viruses. Rondle & Dumbell (1962) have shown that white pock variants of cowpox virus fail to produce a specific, precipitating antigen which they called 'd' substance. In this paper it is shown that 'd' is demonstrable in soluble antigen preparations of rabbitpox virus and of neurovirulent strains of vaccinia virus but not in soluble antigens of variola viruses. Two series of recombinant viruses prepared by Dumbell & Bedson (1964) from variola and cowpox and from variola and rabbitpox viruses were tested for the production of 'd' substance. These results were compared with the previously recorded effects of these recombinants when inoculated intradermally in rabbits. It is concluded that functional genes determining the production of 'd' and of rabbit skin pathogenicity are closely linked on the pox virus genome, but that there is insufficient evidence to say that the two functions are interdependent.

Animals↗

Feline immunodeficiency virus infection of cats as a model to test the effect of certain in vitro selection pressures on the infectivity and virulence of resultant lentivirus variants.

Three groups of specific pathogen-free (SPF) domestic cats, each containing 5 animals, were infected with one of three closely related FIV variants and monitored for 36 weeks. A fourth group of 5 cats was sham-infected and served as uninfected controls. FIV variants included: (1) a fully virulent animal passaged FIV-Petaluma; (2) a Crandell feline kidney (CrFK) cell-adapted FIV-Petaluma (FIV-CrFK); and (3) a variant of FIV-CrFK (FIV-CrFKAZT) that had been selected in vitro for resistance to azidothymidine. Cats infected with fully virulent FIV-Petaluma strongly seroconverted, became persistently viremic, and exhibited lymphadenopathy, neutropenia, and inversion of the CD4+:CD8+ T cell ratio. Cats infected with FIV-CrFK seroconverted but the antibody responses were much weaker and more variable; two of the cats became transiently viremic and no hematologic abnormalities or clinical signs of illness other than a very mild lymphadenopathy were observed. None of the five cats inoculated with FIV-CrFKAZT seroconverted, became viremic, or exhibited any gross or hematologic signs of disease, even though proviral DNA was transiently detected in tissue following inoculation. This study demonstrates that the FIV infection model can be used to assess differences in the virulence of FIV variants, including variants selected for antiretroviral drug resistance.

Animals↗

Consequences of the molecular mechanism of amyloid formation for the understanding of the pathogenesis of Alzheimer's disease and the development of therapeutic strategies.

Amyloid formation in the brain is diagnostic of Alzheimer's disease (AD). However, it is not known whether amyloidogenesis precedes and possibly causes cell death or is a byproduct of cell lysis. In any event, it is critical to understand the time course of amyloid formation. The mechanism of amyloidogenesis has been studied in a simple in vitro model system which can be modified to dissect the factors which may be important in vivo. The studies described herein deal with two factors which are known to be important in vivo; the length of the beta protein C-terminus and the endogenous molecule apolipoprotein E (apoE). It could be shown that the C-terminal sequence of the beta-amyloid protein is a critical determinant of the rate of amyloid formation. This discovery led us to propose that the production of the C-terminally extended variants may be a pathogenic event in familial AD. The APOE allele has been shown to be a susceptibility factor for non-familial AD. The apoE variants have been shown to be amyloid nucleation inhibitors. These proteins probably serve as endogenous amyloid suppressors.

Alzheimer Disease↗

Phenotypic manifestations and variant reclassification of germline PTEN variants: a nationwide Danish study.

BACKGROUND: Classification of heterozygous germline PTEN variants in patients with, or suspected of having, PTEN hamartoma tumour syndrome (PHTS) remains challenging. Accurate classification is essential as these patients require lifelong cancer surveillance. METHODS: We identified all patients with a PTEN variant previously classified as a variant of uncertain significance (VUS), likely pathogenic (LP) or pathogenic (P), collected clinical data and reclassified all variants using the latest PTEN gene-specific American College of Medical Genetics (ACMG) guidelines. Moreover, genotype-phenotype correlations were assessed. RESULTS: 167 patients from 112 families were enrolled. Eighty-seven unique PTEN variants were identified, including 20 novel variants. After applying the PTEN gene-specific ACMG guidelines, 32 variants (36.8%) were reclassified, resulting in 60 PTEN variants classified as LP/P (69.0%), 18 variants classified as VUS (20.7%), while 9 variants were classified as LB/B (10.3%). Genotype-phenotype correlation was performed among 104 patients with LP/P variants: 51 cancer cases were recorded in 41 patients and a distinct PHTS phenotype was observed in 25% of patients, with macrocephaly being present in 99% of patients with a known head circumference. Twenty-three patients had neurodevelopmental delay and/or autism, and we observed an increased prevalence of missense variants in these patients. CONCLUSION: We identified 87 different PTEN variants, and application of PTEN gene-specific ACMG guidelines led to reclassification of 32 variants (36.8%), underscoring the importance of regular variant reassessment using the most recent gene-specific guidelines, ensuring optimal patient management and surveillance.

Genetic Predisposition to Disease↗

Mutations in the dopamine beta-hydroxylase gene are associated with human norepinephrine deficiency.

Norepinephrine (NE), a key neurotransmitter of the central and peripheral nervous systems, is synthesized by dopamine beta-hydroxylase (DBH) that catalyzes oxidation of dopamine (DA) to NE. NE deficiency is a congenital disorder of unknown etiology, in which affected patients suffer profound autonomic failure. Biochemical features of the syndrome include undetectable tissue and circulating levels of NE and epinephrine, elevated levels of DA, and undetectable levels of DBH. Here, we report identification of seven novel variants including four potentially pathogenic mutations in the human DBH gene (OMIM 223360) from analysis of two unrelated patients and their families. Both patients are compound heterozygotes for variants affecting expression of DBH protein. Each carries one copy of a T-->C transversion in the splice donor site of DBH intron 1, creating a premature stop codon. In patient 1, there is a missense mutation in DBH exon 2. Patient 2 carries missense mutations in exons 1 and 6 residing in cis. We propose that NE deficiency is an autosomal recessive disorder resulting from heterogeneous molecular lesions at DBH.

Animals↗

Targeted long-read genomic and epigenomic profiling enhances timely comprehensive variant discovery in hypotonia and muscle weakness.

BACKGROUND: Identifying the genetic basis of hypotonia and muscle weakness is critical for patient management and family counseling. However, diagnosis is often hindered by diverse genomic alterations, including repeat expansions, structural variants (SVs), and methylation defects. Standard-of-care testing, largely based on short-read sequencing, is limited in its ability to detect this heterogeneous variation landscape, leaving many patients undiagnosed or requiring lengthy sequential testing. Long-read sequencing represents a promising solution. However, its application as a first-tier diagnostic assay for hypotonia remains unexplored. METHODS: We retrospectively analyzed 227 patients with hypotonia to assess diagnostic yield, time-to-diagnosis, and costs associated with standard-of-care testing. A long-read whole-genome sequencing (LR-WGS) workflow with targeted analysis of hypotonia-associated genes was developed to detect and prioritize pathogenic SNVs, SVs, and CNVs, repeat expansions, and methylation changes at key disease loci. The workflow was validated in a reference-positive cohort with known diagnoses (n = 15) and applied to an unsolved cohort (n = 14). Variant interpretation followed ACMG guidelines and was confirmed with orthogonal methods. RESULTS: Standard-of-care testing achieved a diagnostic yield of 42% with an average time-to-diagnosis of 68.7 days; however, 30% of diagnosed patients experienced significant delays (average 169 days) due to sequential testing. The LR-WGS based approach identified all known pathogenic variants in the positive cohort, including SMN1 deletions, methylation defects at 15q11.2/Prader-Willi locus, FMR1 repeat expansions, and sequence and copy-number variants in > 100 genes underlying myopathies and muscular dystrophies. The targeted long-read pipeline reduced prioritized variant calls by 97.9-99.9% and, in the unsolved cohort, yielded one definitive diagnosis (de novo COL6A3 deletion) and one possible diagnosis (aberrant methylation and copy number at POMK), for an additional 14% yield. Among patients diagnosed after sequential testing (n = 29), LR-WGS is expected to reduce time-to-diagnosis by ~ 85% and decrease cumulative diagnostic delays, with projected healthcare cost savings of $396,000-439,000. Across the entire 227 patient cohort, LR-WGS is anticipated to reduce testing costs by 6.5%, yielding an average savings of $105 per patient. CONCLUSIONS: LR-WGS enables comprehensive discovery of genomic and epigenomic variants in hypotonia and muscle weakness, improving diagnostic yield, shortening diagnostic timelines, and reducing costs compared with current standard-of-care testing.

Humans↗

Generation of oncogenic mouse type C viruses: in vitro selection of carcinoma-inducing variants.

Type C retroviruses are endogenous in most vertebrate species. These viruses generally are of low pathogenicity in their natural hosts. Variants that contain cell-derived transforming genes have been isolated infrequently in the past upon continued passage in vivo. We report here a procedure that allows the isolation of new mouse leukemia-, sarcoma-, and carcinoma-inducing type C viruses entirely in cell culture. The viruses generated after passage in chemically transformed mouse cells and selectron in epithelial mink lung cells produced pulmonary adenomas and adenocarcinomas and also ovarian carcinomas. Viruses with cell-transforming capacity, as determined by their ability to induce normal murine or mink cells to form progressively growing colonies in soft agar, appeared only transiently (2-4 days) after acute infection of "spontaneously" or chemically transformed mouse cells by nontransforming helper viruses. These transiently appearing transforming viruses can be "captured" by selecting the cells that respond to their newly acquired growth-stimulating ability. This system may lend itself to the systematic isolation of tissue-specific transforming functions from any cell that can be efficiently infected by retroviruses.

Adenoma↗

Effect of interferons and poly(I):poly(C) on the pathogenesis of the diabetogenic variant of encephalomyocarditis virus in different mouse strains.

Interferon (IFN) can either prevent or exacerbate the pathogenic effects of the diabetogenic variant of encephalomyocarditis (EMC-D) virus. The effect seen is dependent upon the mouse strain and the time of IFN administration. For example, IFN-alpha beta protects SWR/J but not ICR Swiss male mice against the diabetogenic effects of the virus. Administration of either IFN-alpha beta or the IFN-inducer poly(I):poly(C) 4 days post infection, results in an exacerbation of the infection in ICR Swiss and C57BL/6 male mice. Studies have been initiated to investigate the role of the IFN system in the pathogenesis of this virus infection. In this study IFNs or poly(I):poly(C) were administered to several mouse strains at 24 h before or 4 days after infection with EMC-D virus. The results of such treatment ranged from complete protection of the animals from the diabetogenic effects of the virus to exacerbation of the infection as reflected by the virus content in selected organs. The effect was dependent upon the mouse strain, the type of IFN, and the time of its administration in relation to virus infection.

Animals↗

SIV escape mutants in rhesus macaques vaccinated with NEF-derived lipopeptides and challenged with pathogenic SIVmac251.

BACKGROUND: Emergence of viral variants that escape CTL control is a major hurdle in HIV vaccination unless such variants affect gene regions that are essential for virus replication. Vaccine-induced multispecific CTL could also be able to control viral variants replication. To explore these possibilities, we extensively characterized CTL responses following vaccination with an epitope-based lipopeptide vaccine and challenge with pathogenic SIVmac251. The viral sequences corresponding to the epitopes present in the vaccine as well as the viral loads were then determined in every macaque following SIV inoculation. RESULTS: In most cases, the emergence of several viral variants or mutants within vaccine CTL epitopes after SIV challenge resulted in increased viral loads except for a single macaque, which showed a single escape viral variant within its 6 vaccine-induced CTL epitopes. CONCLUSION: These findings provide a better understanding of the evolution of CD8+ epitope variations after vaccination-induced CTL expansion and might provide new insight for the development of an effective HIV vaccine.

Animals↗

Maternal genetic variants associated with aneuploid conception: a narrative review.

BACKGROUND: Human aneuploid conception, a leading cause of infertility, pregnancy loss, and congenital disorders (e.g. Down's syndrome), arises from errors in chromosome segregation during oocyte meiosis or embryonic mitosis. While advanced maternal age is a well-established risk factor, significant inter-individual variation exists among younger women, suggesting a substantial role for maternal genetic determinants. OBJECTIVE AND RATIONALE: This review summarizes the identified maternal genetic variants associated with aneuploid conceptions and highlights directions for future research. SEARCH METHODS: We systematically searched PubMed, Embase, and the Cochrane Library (up to 12 January 2026), using key terms related to maternal genetics, genetic variants, aneuploidy, and pregnancy. Inclusion criteria were human studies, genetic confirmation of aneuploidy (in oocytes/embryos/products of conception/fetal cells), maternal variants (rare single-nucleotide variations, single-nucleotide polymorphisms, and small indels [≤50 bp]), and English-language publications. Exclusion criteria were non-human studies, structural/non-aneuploid numerical abnormalities, paternal factors, and conference abstracts. Extracted data items included study identifiers, population characteristics, variant details, detection methods, clinical phenotypes, type and origin of aneuploidy, pathogenicity or effect assessment, and gene inclusion in currently commercially available infertility next-generation sequencing (NGS) panels. Rare variants were classified per American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines, whereas common variants were evaluated based on effect estimates and functional validation. Study quality was appraised using a modified Newcastle-Ottawa Scale. Supplementary searches explored associations between the identified genes and a broader range of reproductive phenotypes. OUTCOMES: From 28 studies covering the broad clinical spectrum of aneuploid pregnancies (including embryo arrest, implantation failure, pregnancy loss, hydatidiform mole, and fetal aneuploidy), we identified maternal variants associated with aneuploid conceptions. These were functionally categorized into meiotic recombination, spindle dynamics, checkpoint enforcement, and the maternal-to-zygotic transition. Among them, variants in several genes are supported by higher-quality evidence, including likely pathogenic rare variants in KIF18A, ELL3, and CEP120, as well as common variants in PLK4 and CCDC66. Although some identified genes (HFM1, MCM9, MEI1, BUB1B, NLRP2, NLRP7, and TLE6) are included in commercial infertility NGS panels, their direct association with aneuploidy requires further validation. WIDER IMPLICATIONS: This review proposes that 'aneuploidy predisposition' constitutes a critical, mechanism-driven dimension for the genetic diagnosis of infertility, complementing phenotype-based frameworks. This approach would best serve women with unexplained infertility and a normal karyotype who have either a history of recurrent aneuploidy or heterogeneous reproductive phenotypes across different cycles. Adopting this perspective refines clinical genetic testing paradigms and underscores the need to prioritize artificial intelligence-enhanced clinico-genomic association studies and develop polygenic risk models integrated with clinical factors. PROSPERO REGISTRATION NUMBER: CRD42025636217.

Humans↗

De Novo TRIO Missense Variants Disrupt Ras-GEF Domains and Cause Congenital Ventriculomegaly and Hydrocephalus.

Congenital hydrocephalus (CH), characterized by congenital ventriculomegaly (CV), affects approximately 0.5-1 per 1000 live births and is a common cause of pediatric neurosurgical intervention, yet its genetic architecture remains incompletely defined. We report a child with syndromic CH requiring cerebrospinal fluid diversion who harbored a pathogenic de novo missense variant in TRIO (c.3232C > T; p.(Arg1078Trp)), a gene previously associated with autosomal dominant neurodevelopmental disorders featuring variable head circumference. This case prompted systematic evaluation of TRIO variation in our CV/CH cohort (2,697 patient-parent trios) using exome sequencing. We identified five additional unrelated probands with de novo TRIO variants, including two novel substitutions affecting the same residue within the Ras-GEF1 domain (p.(Glu1299Lys) and p.(Glu1299Gly)), yielding significant gene-level enrichment for protein-damaging de novo variants (adjusted p = 6.12 × 10-5). All affected individuals exhibited CV, frequently accompanied by developmental delay and additional structural brain abnormalities. In silico structural modeling predicted that associated variants destabilize critical TRIO Ras-GEF domains required for Rho GTPase activation. Analysis of single-nucleus transcriptomic data from the developing human neocortex revealed enrichment of TRIO expression in multipotent progenitor populations. A systematic literature review identified six additional individuals with TRIO de novo variants and reported CV or CH, including an unrelated patient with the same p.(Arg1078Trp) substitution. Together, these findings expand the phenotypic spectrum associated with pathogenic TRIO variation to include CV/CH and support TRIO as a clinically relevant gene in the genetic evaluation of syndromic CV/CH patients.

Humans↗

Biallelic variants in ZNF142 lead to a syndromic neurodevelopmental disorder.

Biallelic variants of the gene encoding for the zinc-finger protein 142 (ZNF142) have recently been associated with intellectual disability (ID), speech impairment, seizures, and movement disorders in nine individuals from five families. In this study, we obtained phenotype and genotype information of 26 further individuals from 16 families. Among the 27 different ZNF142 variants identified in the total of 35 individuals only four were missense. Missense variants may give a milder phenotype by changing the local structure of ZF motifs as suggested by protein modeling; but this correlation should be validated in larger cohorts and pathogenicity of the missense variants should be investigated with functional studies. Clinical features of the 35 individuals suggest that biallelic ZNF142 variants lead to a syndromic neurodevelopmental disorder with mild to moderate ID, varying degrees of delay in language and gross motor development, early onset seizures, hypotonia, behavioral features, movement disorders, and facial dysmorphism. The differences in symptom frequencies observed in the unpublished individuals compared to those of published, and recognition of previously underemphasized facial features are likely to be due to the small sizes of the previous cohorts, which underlines the importance of larger cohorts for the phenotype descriptions of rare genetic disorders.

Humans↗

Analysis of IFT74 as a candidate gene for chromosome 9p-linked ALS-FTD.

BACKGROUND: A new locus for amyotrophic lateral sclerosis--frontotemporal dementia (ALS-FTD) has recently been ascribed to chromosome 9p. METHODS: We identified chromosome 9p segregating haplotypes within two families with ALS-FTD (F476 and F2) and undertook mutational screening of candidate genes within this locus. RESULTS: Candidate gene sequencing at this locus revealed the presence of a disease segregating stop mutation (Q342X) in the intraflagellar transport 74 (IFT74) gene in family 476 (F476), but no mutation was detected within IFT74 in family 2 (F2). While neither family was sufficiently informative to definitively implicate or exclude IFT74 mutations as a cause of chromosome 9-linked ALS-FTD, the nature of the mutation observed within F476 (predicted to truncate the protein by 258 amino acids) led us to sequence the open reading frame of this gene in a large number of ALS and FTD cases (n = 420). An additional sequence variant (G58D) was found in a case of sporadic semantic dementia. I55L sequence variants were found in three other unrelated affected individuals, but this was also found in a single individual among 800 Human Diversity Gene Panel samples. CONCLUSION: Confirmation of the pathogenicity of IFT74 sequence variants will require screening of other chromosome 9p-linked families.

Amyotrophic Lateral Sclerosis↗