Disease-causing Gene Variants Research Articles

Whole Exome Sequencing as an Effective Molecular Diagnosis Tool for Craniofacial Fibrous Dysplasia with Ocular Complications

Purpose To summarize the clinical manifestations of craniofacial fibrous dysplasia (CFD) patients with ocular complications, and find effective methods to diagnose early. Methods Nine CFD patients with ocular complications, and their parents were recruited in this study. All patients underwent ocular and systemic examinations. Bone lesions from all patients and peripheral blood from patients and their parents were collected for whole exome sequencing (WES). According to the screening for low-frequency deleterious variants, and bioinformatics variants prediction software, possible disease-causing variants were found in multiple CFD patients. The variants were validated by Sanger sequencing. Trio analysis was performed to verify the genetic patterns of CFD. Results All patients were diagnosed with CFD, according to the clinical manifestations, classic radiographic appearance, and pathological biopsy. The main symptoms of the 9 CFD patients, included visual decline (9/9), craniofacial deformity (3/9) and strabismus (2/9), with few extraocular manifestations. The family backgrounds of all the CFD patients indicated that only the patient was affected, and their immediate family members were normal. GNAS variants were identified in all bone lesions from CFD patients, including two variant types: c.601C > T:p.R201C(6/9) and c.602G > A:p.R201H (3/9) in exon 8. The detection rate reached 100% by WES, but only 77.8% by Sanger sequencing. Interestingly, we found GNAS variants could not be detected in peripheral blood samples from CFD patients or their parents, and other potentially disease-causing gene variants related to CFD were not found. Conclusions For CFD patients with bone lesions involving the optic canal or sphenoid sinus regions, ocular symptoms should also be considered. Furthermore, we confirmed that CFD is not inherited, somatic variants in the GNAS gene are the main pathogenic gene causing CFD. Compared to the traditional methods in molecular genetic diagnosis of CFD, WES is more feasible and effective but limited in the type of samples.

Characterization of 35 novel NR5A1/SF-1 variants identified in individuals with atypical sexual development: The SF1next study.

Steroidogenic factor 1 (NR5A1/SF-1) is a nuclear receptor that regulates sex development, steroidogenesis and reproduction. Genetic variants in NR5A1/SF-1 are common among differences of sex development (DSD) and associate with a wide range of phenotypes, but their pathogenic mechanisms remain unclear. Novel, likely disease-causing NR5A1/SF-1 variants from the SF1next cohort of individuals with DSD were characterized to elucidate their pathogenic effect. Different in silico tools were used to predict the impact of novel NR5A1/SF-1 variants on protein function. An extensive literature review was conducted to compare and select the best functional studies for testing the pathogenic effect of the variants in a classic cell culture model. The missense NR5A1/SF-1 variants were tested on the promoter luciferase reporter vector -152CYP11A1_pGL3 in HEK293T cells and assessed for their cytoplasmic/nuclear localization by Western blot. Thirty-five novel NR5A1/SF-1 variants were identified in the SF1next cohort. Seventeen missense NR5A1/SF-1 variants were functionally tested. Transactivation assays showed reduced activity for 40% of the variants located in the DNA binding domain and variable activity for variants located elsewhere. Translocation assessment revealed three variants (3/17) with affected nuclear translocation. No clear genotype-phenotype, structure-function correlation was found. Genetic analyses and functional assays do not explain the observed wide phenotype of individuals with these novel NR5A1/SF-1 variants. In nine individuals, additional likely disease-causing variants in other genes were found, strengthening the hypothesis that the broad phenotype of DSD associated with NR5A1/SF-1 variants may be caused by an oligogenic mechanism.

Omenn Syndrome in Two Infants with Different Hypomorphic Variants in Janus Kinase 3.

Biallelic null or hypomorphic variants in JAK3 cause SCID and less frequently Omenn syndrome. We investigated homozygous hypomorphic JAK3 mutations in two patients, and expression and function of a novel JAK3R431P variant in Omenn syndrome. Immunophenotyping of PBMC from the patient with the novel JAK3R431P variant was undertaken, by flow cytometry and Phosflow after stimulation with IL-2, IL-7, and IL-15. JAK3 expression was investigated by Western blotting. We report two patients with homozygous hypomorphic JAK3 variants and clinical features of Omenn syndrome. One patient had a previously described JAK3R775H variant, and the second had a novel JAK3R431P variant. One patient with a novel JAK3R431P variant had normal expression of JAK3 in immortalised EBV-LCL cells but reduced phosphorylation of STAT5 after stimulation with IL-2, IL-7, and IL-15 consistent with impaired kinase activity. These results suggest the JAK3R431P variant to be hypomorphic. Both patients are alive and well after allogeneic haematopoietic stem cell transplantation. They have full donor chimerism, restitution of thymopoiesis and development of appropriate antibody responses following vaccination. We expand the phenotype of hypomorphic JAK3 deficiency and demonstrate the importance of functional testing of novel variants in disease-causing genes.

Implication of transcription factor FOXD2 dysfunction in syndromic congenital anomalies of the kidney and urinary tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) are the predominant cause for chronic kidney disease below age 30 years. Many monogenic forms have been discovered due to comprehensive genetic testing like exome sequencing. However, disease-causing variants in known disease-associated genes only explain a proportion of cases. Here, we aim to unravel underlying molecular mechanisms of syndromic CAKUT in three unrelated multiplex families with presumed autosomal recessive inheritance. Exome sequencing in the index individuals revealed three different rare homozygous variants in FOXD2, encoding a transcription factor not previously implicated in CAKUT in humans: a frameshift in the Arabic and a missense variant each in the Turkish and the Israeli family with segregation patterns consistent with autosomal recessive inheritance. CRISPR/Cas9-derived Foxd2 knock-out mice presented with a bilateral dilated kidney pelvis accompanied by atrophy of the kidney papilla and mandibular, ophthalmologic, and behavioral anomalies, recapitulating the human phenotype. In a complementary approach to study pathomechanisms of FOXD2-dysfunction-mediated developmental kidney defects, we generated CRISPR/Cas9-mediated knock-out of Foxd2 in ureteric-bud-induced mouse metanephric mesenchyme cells. Transcriptomic analyses revealed enrichment of numerous differentially expressed genes important for kidney/urogenital development, including Pax2 and Wnt4 as well as gene expression changes indicating a shift towards a stromal cell identity. Histology of Foxd2 knock-out mouse kidneys confirmed increased fibrosis. Further, genome-wide association studies suggest that FOXD2 could play a role for maintenance of podocyte integrity during adulthood. Thus, our studies help in genetic diagnostics of monogenic CAKUT and in understanding of monogenic and multifactorial kidney diseases.

Germline genetic variants in Turkish familial multiple myeloma/monoclonal gammopathy of undetermined significance cases.

Multiple myeloma (MM) is a haematological malignancy primarily affecting the elderly, with a striking male predilection and ethnic disparities in incidence. Familial predisposition to MM has long been recognized, but the genetic underpinnings remain elusive. This study aimed to investigate germline variants in Turkish families with recurrent MM cases. A total of 37 MM-affected families, comprising 77 individuals, were included. Targeted next-generation sequencing analysis yielded no previously reported rare variants. Whole exome sequencing analysis in 11 families identified rare disease-causing variants in various genes, some previously linked to familial MM and others not previously associated. Notably, genes involved in ubiquitination, V(D)J recombination and the PI3K/AKT/mTOR pathway were among those identified. Furthermore, a specific variant in BNIP1 (rs28199) was found in 13 patients across nine families, indicating its potential significance in MM pathogenesis. While this study sheds light on genetic variations in familial MM in Turkey, its limitations include sample size and the absence of invivo investigations. In conclusion, familial MM likely involves a polygenic inheritance pattern with rare, disease-causing variants in various genes, emphasizing the need for international collaborative efforts to unravel the intricate genetic basis of MM and develop targeted therapies.

Plain language summary of a study looking at whether genetic testing can help doctors diagnose the severity of mucopolysaccharidosis type I (MPS I)

What is MPS I & what is this study about? Mucopolysaccharidosis type I (MPS I) is a rare genetic condition, resulting from disease-causing changes in the IDUA gene called pathogenic variants. There are two different types of variants: Null variants – cells cannot make the alpha-L-iduronidase enzyme Missense variants – cells make a partly functional or severely reduced amount of the fully functional enzyme The alpha-L-iduronidase enzyme breaks down large sugar molecules called glycosaminoglycans (GAGs). In people with MPS I, the enzyme is unable to break down GAGs and they build up in cells. Based on the severity of the condition, doctors categorise MPS I into two types, called phenotypes: Attenuated MPS I Severe MPS I Treatment options differ depending on MPS I phenotype. There are currently no tests that accurately determine MPS I phenotype. Using information from the MPS I Registry, researchers wanted to find out whether knowing the specific combination of the 2 disease-causing gene variants (genotype) can help predict whether a person has an attenuated or severe phenotype. What were the results? In people with attenuated MPS I: 19 in 20 had genotypes where at least one of the gene copies was a missense variant. The cell makes a partly functional or a severely reduced amount of the fully functional enzyme, and is unable to completely break down GAG No-one had 2 null variants 2 in 5 had unique genotypes (their genotype was only seen in one person) In people with severe MPS I: 2 in 3 had genotypes where both copies of the gene contained null variants. The cell is not able to make any enzyme 1 in 5 had unique genotypes What do the results mean? This study showed that genotype can predict phenotype in some people with MPS I. For example, if a person has inherited two copies of the genes containing null variants, they will have severe MPS I. However, due to the large number of unique gene variants found in this study, doctors cannot predict the severity of MPS I from just the genotype for some people.

Whole-Genome Sequencing Can Identify Clinically Relevant Variants from a Single Sub-Punch of a Dried Blood Spot Specimen.

The collection of dried blood spots (DBS) facilitates newborn screening for a variety of rare, but very serious conditions in healthcare systems around the world. Sub-punches of varying sizes (1.5-6 mm) can be taken from DBS specimens to use as inputs for a range of biochemical assays. Advances in DNA sequencing workflows allow whole-genome sequencing (WGS) libraries to be generated directly from inputs such as peripheral blood, saliva, and DBS. We compared WGS metrics obtained from libraries generated directly from DBS to those generated from DNA extracted from peripheral blood, the standard input for this type of assay. We explored the flexibility of DBS as an input for WGS by altering the punch number and size as inputs to the assay. We showed that WGS libraries can be successfully generated from a variety of DBS inputs, including a single 3 mm or 6 mm diameter punch, with equivalent data quality observed across a number of key metrics of importance in the detection of gene variants. We observed no difference in the performance of DBS and peripheral-blood-extracted DNA in the detection of likely pathogenic gene variants in samples taken from individuals with cystic fibrosis or phenylketonuria. WGS can be performed directly from DBS and is a powerful method for the rapid discovery of clinically relevant, disease-causing gene variants.

Identified eleven exon variants in PKD1 and PKD2 genes that altered RNA splicing by minigene assay

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is a common monogenic multisystem disease caused primarily by mutations in the PKD1 gene or PKD2 gene. There is increasing evidence that some of these variants, which are described as missense, synonymous or nonsense mutations in the literature or databases, may be deleterious by affecting the pre-mRNA splicing process.ResultsThis study aimed to determine the effect of these PKD1 and PKD2 variants on exon splicing combined with predictive bioinformatics tools and minigene assay. As a result, among the 19 candidate single nucleotide alterations, 11 variants distributed in PKD1 (c.7866C > A, c.7960A > G, c.7979A > T, c.7987C > T, c.11248C > G, c.11251C > T, c.11257C > G, c.11257C > T, c.11346C > T, and c.11393C > G) and PKD2 (c.1480G > T) were identified to result in exon skipping.ConclusionsWe confirmed that 11 variants in the gene of PKD1 and PKD2 affect normal splicing by interfering the recognition of classical splicing sites or by disrupting exon splicing enhancers and generating exon splicing silencers. This is the most comprehensive study to date on pre-mRNA splicing of exonic variants in ADPKD-associated disease-causing genes in consideration of the increasing number of identified variants in PKD1 and PKD2 gene in recent years. These results emphasize the significance of assessing the effect of exon single nucleotide variants in ADPKD at the mRNA level.

Comprehensive genetic screening of early-onset dementia patients in an Austrian cohort-suggesting new disease-contributing genes

Early-onset dementia (EOD), with symptom onset before age 65, has a strong genetic burden. Due to genetic and clinical overlaps between different types of dementia, whole-exome sequencing (WES) has emerged as an appropriate screening method for diagnostic testing and novel gene-finding approaches. We performed WES and C9orf72 repeat testing in 60 well-defined Austrian EOD patients. Seven patients (12%) carried likely disease-causing variants in monogenic genes, PSEN1, MAPT, APP, and GRN. Five patients (8%) were APOE4 homozygote carriers. Definite and possible risk variants were detected in the genes TREM2, SORL1, ABCA7 and TBK1. In an explorative approach, we cross-checked rare gene variants in our cohort with a curated neurodegeneration candidate gene list and identified DCTN1, MAPK8IP3, LRRK2, VPS13C and BACE1 as promising candidate genes. Conclusively, 12 cases (20%) carried variants relevant to patient counseling, comparable to previously reported studies, and can thus be considered genetically resolved. Reduced penetrance, oligogenic inheritance and not yet identified high-risk genes might explain the high number of unresolved cases. To address this issue, we provide complete genetic and phenotypic information (uploaded to the European Genome-phenome Archive), enabling other researchers to cross-check variants. Thereby, we hope to increase the chance of independently finding the same gene/variant-hit in other well-defined EOD patient cohorts, thus confirming new genetic risk variants or variant combinations.

Gene Panel Sequencing Analysis Revealed a Strong Contribution of Rare Coding Variants to the Risk of Parkinson's Disease in Sporadic Moroccan Patients.

Parkinson's disease (PD) is a neurodegenerative movement disorder which can be either familial or sporadic. While it is well known that monogenic mutations are not a very common cause of PD, GWAS studies have shown that an additional fraction of the PD heritability could be explained by rare or common variants. To identify the rare variants that could influence the risk of PD in the Moroccan population, a cohort of 94 sporadic PD patients negative for the LRRK2 G2019S mutation was subjected to NGS gene panel sequencing, and gene dosage using the MLPA method. Mean age of onset at enrollment was 51.7 ± 11.51years, and 60% of patients were men. We identified 70 rare variants under 0.5% of frequency in 16 of the 20 genes analyzed, of which 7 were novel. Biallelic disease-causing variants in genes with recessive inheritance were found in 5 PD cases (5.31%), whereas 13 patients (13.8%) carried likely pathogenic variants in genes with dominant inheritance. Moreover, 8 patients (8.5%) carried a single variant in MAPT or POLG, whereas co-occurrence of rare variants involving more than one gene was observed in 28 patients (30%). PD patients with variants in recessive genes had a younger mean age at onset than patients with dominant ones (33.40 (12.77) vs. 53.15 (6.63), p < 0.001), while their clinical features were similar. However, patients with rare variants in the risk factor genes or in more than one gene tended to have less resting tremor (p < 0.04), but more dystonia (p < 0.006) and dementia (p < 0.002) than those without any rare variants in known PD-associated genes. Our results showed a significant enrichment of rare variants particularly in LRRK2, VPS13C, POLG, and MAPT and underline their impact on the risk of sporadic form of the disease.

Copeptin in autosomal dominant polycystic kidney disease: real-world experiences from a large prospective cohort study.

The identification of new biomarkers in autosomal-dominant polycystic kidney disease (ADPKD) is crucial to improve and simplify prognostic assessment as a basis for patient selection for targeted therapies. Post hoc analyses of the TEMPO 3:4 study indicated that copeptin could be one of those biomarkers. Copeptin was tested in serum samples from patients of the AD(H)PKD study. Serum copeptin levels were measured using a time-resolved amplified cryptate emission (TRACE)-based assay. In total, we collected 711 values from 389 patients without tolvaptan treatment and a total of 243 values (of which 64 were pre-tolvaptan) from 94 patients on tolvaptan. These were associated with rapid progression and disease-causing gene variants and their predictive capacity tested and compared with the Mayo Classification. As expected, copeptin levels showed a significant negative correlation with estimated glomerular filtration rate (eGFR). Measurements on tolvaptan showed significantly higher copeptin levels (9.871pmol/L vs 23.90pmol/L at 90/30mg; P<.0001) in all chronic kidney disease stages. Linear regression models (n=133) show that copeptin is an independent predictor of eGFR slope. A clinical model (including eGFR, age, gender, copeptin) was nearly as good (R2=0.1196) as our optimal model (including height-adjusted total kidney volume, eGFR, copeptin, R2=0.1256). Adding copeptin to the Mayo model improved future eGFR estimation. Copeptin levels are associated with kidney function and independently explained future eGFR slopes. As expected, treatment with tolvaptan strongly increases copeptin levels.

Ethics in pre-ART genetics: a missed X-linked Menkes disease case

Assisted reproductive technology (ART) has experienced dramatic progress over the last 30 years, and gamete donation is routine in fertility clinics. Major advances in genetic diagnostics are part of this development due to the ability to analyze multiple genes or whole genomes fast and to an affordable prize. This requires knowledge and capability to evaluate genetic variants correctly in a clinical setting. Here we report a Menkes disease case, born after ART, where genetic screening and variant scoring failed to identify an egg donor as carrier of this fatal X-linked disorder. The gene variant is a deletion of a single base pair leading to a frameshift and premature termination of the protein, predicted to result in no or severely diminished function. The variant would be classified as likely pathogenic (class 4) and should be readily detectable by molecular genetic screening techniques. We wish to highlight this case to prevent future similar cases. IVI Igenomix has developed and embarked on an ambitious screening program to detect and prevent a large number of inherited severe childhood disorders in ART pregnancies. The company has recently achieved ISO 15189 certification with competence to evaluate and deliver timely, accurate, and reliable results. Failure to identify a pathogenic variant in the ATP7A gene leading to birth of two boys with Menkes disease invokes the required procedures to screen and detect disease-causing gene variants. This calls for ethical and legal considerations in ART diagnostics to prevent fatal errors like the present.

Measuring high-risk parents' opinions about direct-to-consumer genetic testing for adult-onset inherited cancer syndromes in their adolescent and young adult children.

Neither direct-to-consumer (DTC) genetic testing nor predictive genetic testing for adult-onset conditions is recommended for minor children due to ethical concerns and low clinical utility. However, parents with pathogenic variants (PVs) in disease-causing genes may be interested in pursuing genetic testing that includes the familial PV for their children. The Pediatric Testing Attitudes Scale (P-TAS) was previously developed to examine high-risk parents' opinions about pediatric BRCA genetic testing for adult-onset breast/ovarian cancer. Here, the psychometric properties of the P-TAS were examined in a new sample of N=126 parents (M age=47.2 years) with PVs in a more complete set of cancer risk genes represented on DTC panel tests. The mean score on the P-TAS was 44 out of a maximum score of 60, indicating that a majority of parents generally held favorable opinions about testing their children for adult-onset inherited cancer syndromes. The internal consistency of the full scale was high (α=0.91). A factor analysis identified two-component scales, labeled Attitudes and Beliefs (α=0.93) and Decision Making and Communication (α=0.83). In a multivariable regression model, P-TAS co-factors accounted for 34% of variance in parental opinions, including the frequency of prior family communication about cancer and the likelihood of utilizing DTC genetic testing with children (R2 =0.34, p < 0.001). Results suggest that the P-TAS remains a reliable measure to assess high-risk parents' opinions about pediatric DTC genetic testing for adult-onset conditions, with promising validity. Applications of the P-TAS include informing genetic counseling practice, pediatric medical care, and policy guidelines surrounding DTC genetic testing.

Different clinical characteristics and outcomes of hypertrophic cardiomyopathy with and without hypertension: seeking the truth.

To determine the different clinical characteristics and outcomes of hypertrophic cardiomyopathy (HCM) patients with and without hypertension (HT). A total of 696 HCM patients were included in this study and all HCM diagnoses were confirmed by the genetic test. Patients were analyzed separately in the septal reduction therapy (SRT) cohort and the non-SRT cohort. The primary endpoint was cardiovascular death and the secondary endpoint was all-cause death. Outcome analyses were conducted to evaluate the associations between HT and outcomes in HCM. Medications before enrollment and at discharge were collected in the post-hoc analyses. HCM patients without HT were younger, had a lower body mass index, were more likely to have a family history of HCM, and had a smaller left ventricular (LV) end-diastolic diameter than those with HT in both cohorts. A thicker LV wall, a higher level of N-terminal pro-B-type natriuretic peptide, and a higher extent of LV late gadolinium enhancement were additionally observed in patients without HT in the non-SRT cohort. The presence of HT did not alter the distribution pattern of late gadolinium enhancement, as well as the constituent ratio of eight disease-causing sarcomeric gene variants in both cohorts. Outcome analyses showed that in the non-SRT cohort, patients without HT had higher risks of cardiovascular death (HR = 2.537, P = 0.032) and all-cause death (HR = 3.309, P = 0.032). While such prognostic divergence was not observed in the SRT cohort. Further post-hoc analyses in the non-SRT cohort found that patients without HT received fewer non-dihydropyridine calcium channel blockers and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers before enrollment and at discharge. HCM patients without HT had worse clinical conditions and higher mortality than patients with HT overall, which may result from active medical therapy in HT patients. Active SRT may have a substantial de-risking effect on patients meeting the indications.

The Genetic Etiology of Parkinson's Disease Does Not Robustly Affect Subthalamic Physiology.

It is unknown whether Parkinson's disease (PD) genetic heterogeneity, leading to phenotypic and pathological variability, is also associated with variability in the unique PD electrophysiological signature. Such variability might have practical implications for adaptive deep brain stimulation (DBS). The aim of our work was to study the electrophysiological activity in the subthalamic nucleus (STN) of patients with PD with pathogenic variants in different disease-causing genes. Electrophysiological data from participants with negative genetic tests were compared with those from GBA, LRRK2, and PRKN-PD. We analyzed data from 93 STN trajectories (GBA-PD: 28, LRRK2-PD: 22, PARK-PD: 10, idiopathic PD: 33) of 52 individuals who underwent DBS surgery. Characteristics of β oscillatory activity in the dorsolateral motor part of the STN were similar for patients with negative genetic tests and for patients with different forms of monogenic PD. The genetic heterogeneity in PD is not associated with electrophysiological differences. Therefore, similar adaptive DBS algorithms would be applicable to genetically heterogeneous patient populations. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Transcript capture and ultradeep long-read RNA sequencing (CAPLRseq) to diagnose HNPCC/Lynch syndrome

PurposeWhereas most human genes encode multiple mRNA isoforms with distinct function, clinical workflows for assessing this heterogeneity are not readily available. This is a substantial shortcoming, considering that up to...

A Comprehensive Study of Disease-Causing Variants in PAH, QDPR, PTS, and PCD Genes in Iranian Patients with Hyperphenylalaninemia: A Systematic Review

Background: Hyperphenylalaninemia (HPA) is an autosomal recessive disorder that results from a deficiency in the phenylalanine hydroxylase enzyme (PAH) or from a flaw in the genes that are responsible for the biosynthesis or regeneration of the cofactor tetrahydrobiopterin (BH4), including GCH1, SR, QDPR, PTS, and PCD. Identification of disease-causing variants in these genes can help physicians and clinical geneticists in differential diagnosis, appropriate prescription drugs, and saving time and cost. This study attempted to identify these genes’ most prevalent disease-causing variants in Iranian HPA patients. Summary: This study was performed under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Before it started, the flow work and inclusion/exclusion criteria were published as a protocol in PROSPERO (CRD42021273705). We conducted a comprehensive search on December 10, 2022, on international online databases, including Web of Science, Scopus, EMBASE, Science Direct, PubMed/Medline, Google Scholar, SID, ISC, and Magiran search engine, to find pertinent publications. Some studies were chosen based on inclusion and exclusion criteria. Altogether, 1,243 Iranian patients from 13 articles were considered. In total, we identified 129 distinct disease-causing variants in PAH (20 novel variants), 29 in QDPR (17 novel variants), 15 in PTS (seven novel variants), and one novel variant in PCD. Twenty disease-causing variants for PAH, 18 for QDPR, and 8 for PTS are included in the genes’ proposed genetic diagnostic panels. These panels include more than 75% of the documented disease-causing variants in the Iranian population. Key Messages: The findings of this research illustrated the spectrum of disease-causing variants in the PAH, QDPR, PTS, and PCD genes identified in Iranian HPA patients. Common disease-causing variants of these genes may be chosen as a preliminary diagnostic panel for early diagnosis and lowering therapy costs.

A novel heterozygous variant in PANX1 causes primary infertility due to oocyte death.

Variants in the pannexin1 (PANX1) gene have been reported to be associated with oocyte death and recurrent in vitro fertilization failure. In this study, we performed genetic analysis in the patient with female infertility due to oocyte death to identify the disease-causing gene variant in the patient. We characterized one patient from a non-consanguineous family who had suffered from oocyte death and female infertility. Whole-exome sequencing and Sanger sequencing were used to identify the variant in the family. Western blot analysis was used to check the effect of the variant on PANX1 glycosylation pattern in vitro. We identified a novel heterozygous PANX1 variant (NM_015368.4 c.976_978del, (p.Asn326del)) associated with the phenotype of oocyte death in a non-consanguineous family, followed by an autosomal dominant (AD) mode. This variant showed a more delayed emergence of oocyte death than previously reported articles. Western blot analysis confirmed that the deletion variant of PANX1 (c.976_978del) altered the glycosylation pattern in HeLa cells. Our findings expand the variant spectrum of PANX1 genes associated with oocyte death and provide new support for the genetic diagnosis of female infertility.

Clinical genetics of spondylocostal dysostosis: A mini review.

Spondylocostal dysostosis is a genetic defect associated with severe rib and vertebrae malformations. In recent years, extensive clinical and molecular diagnosis advancements enabled us to identify disease-causing variants in different genes for such severe conditions. The identification of novel candidate genes enabled us to understand the developmental biology and molecular and cellular mechanisms involved in the etiology of these rare diseases. Here, we discuss the clinical and molecular targets associated with spondylocostal dysostosis, including clinical evaluation, genes, and pathways involved. This review might help us understand the basics of such a severe disorder, which might help in proper clinical characterization and help in future therapeutic strategies.

Genetic evaluation of hyperphenylalaninemia patients with tetrahydrobiopterin deficiency in Iranian population: Identification of four novel disease-causing variants.

Hyperphenylalaninemia (HPA) is the most common inborn error of amino acid metabolism worldwide. At least 2% of HPA cases are caused by a deficiency in tetrahydrobiopterin (BH4) metabolism. Genes such as QDPR and PTS are essential in the BH4 metabolism. This study aims to identify disease-causing variants in HPA patients, which may be helpful in genetic counseling and prenatal diagnosis. A total of 10 HPA patients were enrolled in this study. The coding and adjacent intronic regions of PTS and QDPR genes were examined using Sanger sequencing. Protein modeling was also performed for novel identified variants. Ten patients and a total of 20 alleles were studied, which led to the identification of 10 different variants. All variants identified in PTS and QDPR were missense, except for the c.383_407del variant in the QDPR. Also, three novel variants were identified in the QDPR, including c.79G>T, c.383_407del and c.488G>A, and a novel variant, c.65C>G, in the PTS. Despite the genetic similarities in the disease-causing variants, differences were observed in the Asian and European populations with our populations; As a result, similar but more extensive studies are needed to investigate the distribution of disease-causing variants in genes involved in non-PKU hyperphenylalaninemia.