Reported Missense Mutations Research Articles

In vitro maturation of oocytes is an effective approach for women with resistant ovary syndrome resulting from FSHR inactivating mutations

Research questionIs in vitro maturation (IVM) of oocytes effective for treating resistant ovary syndrome (ROS) in women carrying biallelic FSHR-inactivating mutations? DesignThree patients with ROS were recruited for this study. Candidate pathogenic mutations were identified using whole-exome sequencing (WES). A cAMP production assay was performed to evaluate the effects of these mutations. In vitro maturation (IVM) of oocytes was performed to achieve pregnancy. ResultsAfter initially undergoing conventional in vitro fertilization (c-IVF) in the first cycle, whole exome sequencing (WES) was performed on the three ROS patients and found them carrying biallelic FHSR mutations, including four novel missense mutations (c.263C>T, c.1106T>C, c.211G>T, and c.1349T>A) and one previously reported missense mutation (c.44G>A). A cAMP production assay was performed to evaluate the effects of these mutations, which revealed that these mutations led to an almost complete inactivation of the mutated receptors upon FSH stimulation. Additionally, IVM of the oocytes was performed and blastocysts were successfully obtained from the first two patients. Finally, two patients delivered healthy babies. ConclusionsThe five missense mutations in FSHR were deleterious and associated with ROS in the three families. This is the first report on patients who carried biallelic inactivating FSHR mutations and gave birth to genetically related children after receiving IVM treatment. Our findings show that IVM is an effective treatment for ROS patients with FSHR-inactivating mutations.

Phenotypic, genetic, variation, and molecular function of CaMYB113 in pepper (Capsicum annuum L.).

Pepper (Capsicum annuum L.) is widely consumed vegetables worldwide, and F1 hybrids are highly sought after in the pepper seed industry. However, studies on gene mutations affecting the color of cotyledon are rare, and the same is true for peppers. In this study, a segregating population was developed by crossing the pepper accession 21C1344 with purple cotyledon and accession 21C912 with green cotyledon. Initially, a target genomic region was identified by screening polymorphic SSR markers distributed across 12 chromosomes. Subsequently, polymorphic markers were developed based on resequencing data from the two parental lines, and genetic linkage analysis was performed. This approach ultimately identified Capana10g001433 (CaMYB113) as the candidate gene responsible for the purple cotyledons. The gene mutation type in 21C912 represents a new mutation type distinct from the reported missense mutation types, and this mutation affects the biosynthesis of anthocyanins. Virus-induced gene silencing (VIGS) of CaMYB113 substantially decreased anthocyanin accumulation in the cotyledons. Subsequent overexpression of CaMYB113 resulted in purple callus and leaves of pepper, and changed the expression levels of downstream genes involved in anthocyanin synthesis. Yeast one-hybrid and dual-luciferase transient expression assays demonstrated the binding of CaMYB113 to anthocyanin biosynthesis-related genes, thereby regulating anthocyanin accumulation in pepper cotyledons.

Prevalence and <em>in silico</em> analysis of p.D658G variant of WDR36 gene in patients affected with primary open angle glaucoma from Punjab Pakistan

The aim of the present study was to check the frequency of genetic variants in exons 8, 11, 13, and 17 of the WDR36 gene among primary open angle glaucoma (POAG) patients from Punjab, Pakistan, and to perform the in silico analysis of identified variants on protein function. Ninety-two individuals affected with primary open angle glaucoma were enrolled for this study. The clinical investigation involved the examination of the optic nerve head, visual field loss and elevated intraocular pressure (IOP). Selected exons (8, 11, 13, and 17) of the WDR36 gene was screened by Sanger sequencing. Sequencing results revealed a previously reported missense mutation p.D658G in exon 17 in two out of ninety-two POAG patients, while no mutation has been identified in the exons 8, 11, and 13. To predict the structural and functional effect of the p.D658G variant, SIFT, Polyphen-2, PROVEAN, mutation taster, I-mutant 3.0, and MuPRO were used. The MODELLER-CABS based hybrid approach was used for protein structure modelling. In silico analysis predicted the p.D658G variant to be deleterious, and it may affect the stability of protein and protein-protein interaction. The findings of this study suggested that the genetic variant p.D658G of the WDR36 gene is a rare genetic cause of POAG in Pakistani patients. The in silico tools predicted the variant p.D658G to be deleterious; however the modelled normal and mutant structure showed no effect on protein structure and function. To further confirm the pathogenic effect of this SNP, in vivo experiments, X-ray Crystallography of the WDR36 protein and population-based studies are needed.

Identification of Novel FZD4 Mutations in Familial Exudative Vitreoretinopathy and Investigating the Pathogenic Mechanisms of FZD4 Mutations.

The purpose of this study is to report five novel FZD4 mutations identified in familial exudative vitreoretinopathy (FEVR) and to analyze and summarize the pathogenic mechanisms of 34 of 96 reported missense mutations in FZD4. Five probands diagnosed with FEVR and their family members were enrolled in the study. Ocular examinations and targeted gene panel sequencing were conducted on all participants. Plasmids, each carrying 29 previously reported FZD4 missense mutations and five novel mutations, were constructed based on the selection of mutations from each domain of FZD4. These plasmids were used to investigate the effects of mutations on protein expression levels, Norrin/β-catenin activation capacity, membrane localization, norrin binding ability, and DVL2 recruitment ability in HEK293T, HEK293STF, and HeLa cells. All five novel mutations (S91F, V103E, C145S, E160K, C377F) responsible for FEVR were found to compromise Norrin/β-catenin activation of FZD4 protein. After reviewing a total of 34 reported missense mutations, we categorized all mutations based on their functional changes: signal peptide mutations, cysteine mutations affecting disulfide bonds, extracellular domain mutations influencing norrin binding, transmembrane domain (TM) 1 and TM7 mutations impacting membrane localization, and intracellular domain mutations affecting DVL2 recruitment. We expanded the spectrum of FZD4 mutations relevant to FEVR and experimentally demonstrated that missense mutations in FZD4 can be classified into five categories based on different functional changes.

Identification of novel pathogenic variants of CUBN in patients with isolated proteinuria.

Although proteinuria is long recognized as an independent risk factor for progressive chronic kidney diseases, not all forms of proteinuria are detrimental to kidney function, one of which is isolated proteinuria caused by cubilin (CUBN)-specific mutations. CUBN encodes an endocytic receptor, initially found to be responsible for the Imerslund-Gräsbeck syndrome (IGS; OMIM #261100) characterized by a combined phenotype of megaloblastic anemia and proteinuria. After analyzing their clinical and pathological characterizations, next-generation sequencing for renal disease genes or whole-exome sequencing (WES) was performed on four patients with non-progressive isolated proteinuria. CUBN biallelic pathogenic variants were identified and further analyzed by cDNA-PCR sequencing, immunohistochemistry, minigene assay, and multiple in silico prediction tools, including 3D protein modeling. Here, we present four patients with isolated proteinuria caused by CUBN C-terminal biallelic pathogenic variants, all of which showed no typical IGS symptoms, such as anemia and vitamin B12 deficiency. Their urine protein levels fluctuated between +~++ and estimated glomerular filtration rate (eGFR) were normal or slightly higher. Mild mesangial hypercellularity was found in three children's renal biopsies. A homozygous splice-site variant of CUBN (c.6821+3 (IVS44) A>G) was proven to result in the exon 44 skipping and premature translation termination by cDNA sequencing and immunohistochemistry. Compound heterozygous mutations were identified among the other three children, including another novel splice-site variant (c.10764+1 (IVS66) G>A) causing the retention of first 4 nucleotides in intron 66 by minigene assay, two unreported missense mutations (c.4907G>A (p.R1636Q); c. 9095 A>G (p.Y3032C)), and two reported missense mutations in China (c.8938G>A (p.D2980N); c. 9287T>C (p.L3096P)), locating behind the vitamin B12-binding domain, affecting CUB11, CUB16, CUB22, CUB23, and CUB27 domains, respectively. These results demonstrate that above CUBN mutations may cause non-progressive and isolated proteinuria, expanding the variant spectrum of CUBN and benefiting our understanding of proteinuria and renal function.

In-silico and structure-based assessment to evaluate pathogenicity of missense mutations associated with non-small cell lung cancer identified in the Eph-ephrin class of proteins.

Ephs belong to the largest family of receptor tyrosine kinase and are highly conserved both sequentially and structurally. The structural organization of Eph is similar to other receptor tyrosine kinases; constituting the extracellular ligand binding domain, a fibronectin domain followed by intracellular juxtamembrane kinase, and SAM domain. Eph binds to respective ephrin ligand, through the ligand binding domain and forms a tetrameric complex to activate the kinase domain. Eph-ephrin regulates many downstream pathways that lead to physiological events such as cell migration, proliferation, and growth. Therefore, considering the importance of Eph-ephrin class of protein in tumorigenesis, 7,620 clinically reported missense mutations belonging to the class of variables of unknown significance were retrieved from cBioPortal and evaluated for pathogenicity. Thirty-two mutations predicted to be pathogenic using SIFT, Polyphen-2, PROVEAN, SNPs&GO, PMut, iSTABLE, and PremPS in-silico tools were found located either in critical functional regions or encompassing interactions at the binding interface of Eph-ephrin. However, seven were reported in nonsmall cell lung cancer (NSCLC). Considering the relevance of receptor tyrosine kinases and Eph in NSCLC, these seven mutations were assessed for change in the folding pattern using molecular dynamic simulation. Structural alterations, stability, flexibility, compactness, and solvent-exposed area was observed in EphA3 Trp790Cys, EphA7 Leu749Phe, EphB1 Gly685Cys, EphB4 Val748Ala, and Ephrin A2 Trp112Cys. Hence, it can be concluded that the evaluated mutations have potential to alter the folding pattern and thus can be further validated by in-vitro, structural and in-vivo studies for clinical management.

Clinical, immunological and molecular findings of 8 patients with typical and atypical severe combined immunodeficiency: identification of 7 novel mutations by whole exome sequencing.

Severe combined immunodeficiency (SCID) is one of the severe inborn errors of the immune system associated with life-threatening infections. Variations in SCID phenotypes, especially atypical SCID, may cause a significant delay in diagnosis. Therefore, SCID patients need to receive an early diagnosis. Here, we describe the clinical manifestations and genetic results of four SCID and atypical SCID patients. All patients (4 males and 4 females) in early infancy presented with SCID phenotypes within 6 months of birth. The mutations include RAG2 (p.I273T,p.G44X), IL7R (p.F361WfsTer17), ADA (c.780+1G>A), JAK3 (p.Q228Ter), LIG4 (p.G428R), and LAT (p.Y207fsTer33), as well as a previously reported missense mutation in RAG1 (p.A444V). The second report of LAT deficiency in SCID patients is presented in this study. Moreover, all variants were confirmed in patients and their parents as a heterozygous state by Sanger sequencing. The results of our study expand the clinical and molecular spectrum associated with SCID and leaky SCID phenotypes and provide valuable information for the clinical management of the patients.

33701 Porokeratotic eccrine ostial and dermal duct nevus caused by a second-hit postzygotic GJB2 mutation

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare type of epidermal nevus involving the eccrine acrosyringia. It typically presents as asymptomatic linear keratotic papules and plaques along the lines of Blaschko which predominantly affects the extremities, and the disease has recently been linked to GJB2 somatic mutations. To the best of our knowledge, only four mutations have been documented from GJB2 in pure PEODDN cases. Herein, we reported an 18-year-old female who presented with a hyperkeratotic plaque on the dorsal side of the proximal interphalangeal joint of her right ring finger as well as multiple small linear hyperkeratotic papules distributed over the lateral side of her her right index, middle and ring fingers noted since her birth. Histopathologic study revealed prominent parakeratotic cornoid lamella-like tiers at the opening of eccrine secretory ducts. Sanger sequencing focusing on the GJB2 gene revealed a germline heterozygous missense mutation, c.608T>C (p.Ile203Thr) in the blood and the epidermal tissue of the affected skin. Whole exome sequencing (WES) on the genomic DNA extracted from the lesional epidermis identified another second-hit postzygotic somatic reported missense mutation, c.263C>A (p.Ala88Glu) with low mosaic percentage of around 4% and reflecting the dilutional effect in biopsy of whole tissue and limit of detection by Sanger sequencing. In conclusion, this study presents a case of PEODDN with a complete genetic study identifying a germline mutation and a second-hit postzygotic somatic mutation; our findings strengthen the importance of second- hit somatic mutation in GJB2 as an etiology in PEODDN.

Two New Variants in FYCO1 Are Responsible for Autosomal Recessive Congenital Cataract in Iranian Population.

The purpose of this experimental study was to investigate the genetic etiology of congenital cataract (CC) manifesting an autosomal recessive pattern of inheritance in four Iranian families. Affected individuals and their normal first-degree relatives in each family were included in the present study. The genomic DNA of the blood samples was extracted from all participants, and one affected member belonging to each family was subjected to Whole Exome Sequencing (WES). Using bidirectional Sanger sequencing, the identified variants were validated by co-segregation analysis. Two different mutations were detected in the FYCO1 gene encoding FYVE and coiled-coil domain-containing protein. A previously reported missense mutation, c.265C>T (p.Arg89Cys), was found in one Iranian family for the first time, and a combination of two variants in a single codon, c.[265C>T;267C>A] (p.Arg89X), was identified in the three other families. On the other hand, accompanying the c.265C>T mutation, the presence of the c.267C>A polymorphism leads to a premature stop codon. In-Silico Analysis of FYCO1 protein demonstrated that RUN domain will be interrupted so that the large part of functional protein will be eliminated due to this novel variant. FYCO1 has been proved to be involved in human lens development and transparency. Its mutations, therefore, result in CC. Herein, we reported the first autosomal recessive CC patients with c.265C>T (p.Arg89Cys) or c.[265C>T;267C>A] variant in Iranian population for the FYCO1 gene. FYCO1 mutations could be tracked for preventive objectives or even be targeted as therapeutic candidates via treatment approaches in the future.

Molecular heterogeneity of factor XI deficiency in Tunisia.

Factor XI (FXI) deficiency is a rare inherited bleeding disorder that is highly prevalent in Ashkenazi Jewish ancestry but sporadically observed in most ethnic groups. It is heterogeneous both in clinical presentation and in genetic causality. Although a large spectrum of mutations associated with this disorder has been reported in several populations, genetic data of FXI deficiency in Tunisia are poorly described. The purpose of this study was to determine the molecular basis of FXI deficiency among Tunisian patients. Fourteen index cases from nine unrelated families with FXI deficiency, referred to Hemophilia Treatment Center of Aziza Othmana Hospital, were included in this study. The patients' F11 genes were amplified by PCR and subjected to direct DNA sequencing analysis. Sequencing analysis of F11 genes identified three distinct mutations; the Jewish type II nonsense mutation E117X, one previously reported missense mutation E602Q and one novel missense mutation V271M, which led to the disruption of the third apple domain structure of FXI. Furthermore, seven polymorphisms previously described, were also detected: C321F, c. 294A>G, -138 A>C, p.D125D, p.T249T, p.G379G, p.D551D. This report represents the first genetic study analyzing the molecular characteristics of factor XI deficiency within Tunisian population. Identification of the Jewish type II mutation in two families, as well as one missense previously reported mutation and one novel mutation confirmed the genetic heterogeneity of this disorder. Screening a large number of Tunisian factor XI deficient would reveal the spectrum mutations causing factor XI deficiency in Tunisia.

Novel compound heterozygous cadherin 3 mutations in hypotrichosis and juvenile macular dystrophy.

Novel compound heterozygous cadherin 3 mutations in hypotrichosis and juvenile macular dystrophy.

Clinical and genetic spectrum in Chinese families with Fabry disease: a single-centre case series.

AimsFabry disease (FD) is an X‐linked genetic disease caused by mutations in the GLA gene that leads to deficient activity of lysosomal enzymes, accumulation of globotriaosylceramide in multi‐organ systems, and variant clinical manifestations. We aimed to detail the clinical and genetic spectrum of FD in Chinese families.Methods and resultsFive male probands with unexplained left ventricular hypertrophy and their family members were investigated. Genetic screening was available in 11 subjects of the 5 families, 10 of whom proved to be carriers of either GLA gene mutation, including 3 previous reported missense mutations (c.128G > A, c.811G > A, c.950T > C), 1 novel missense mutation (c.37G > C), and 1 novel deletion mutation (c.1241delT). A total of 17 patients were definitely or possibly diagnosed of FD, given their clinical manifestations and hereditary nature of FD. Echocardiography demonstrated normal cardiac structure and function in six female patients. Electrocardiographic pre‐excitation occurred in 80% (4/5) of men and 16.7% (1/6) of women. Six patients (6/14, 42.9%) had chronic kidney disease with decreased renal function and all were male (6/7, 85.7%). Six patients presented with acroparesthesia, hypohidrosis, or both. Three female patients and two male patients experienced sudden death, and one male patient with the mutation (c.128G > A) died of progressive heart failure, between 41 and 66 years of age.ConclusionsWe reported five unrelated families of FD with different GLA mutations. Clinical manifestations were highly heterogeneous between male and female patients even within the same family. Female patients showed relatively low risks of structural heart disease and renal insufficiency. However, the long‐term outcomes might be adverse in both sexes. Our study underlines the importance of molecular screening of the GLA gene for early identification and clinical decision making in patients with FD.

Phenotypic intrafamilial variability including H syndrome and Rosai\u2013Dorfman disease associated with the same c.1088G\u2009>\u2009A mutation in the SLC29A3 gene

BackgroundMutations in the SLC29A3 gene, which encodes the nucleoside transporter hENT3, have been implicated in syndromic forms of histiocytosis including H syndrome, pigmented hypertrichosis with insulin-dependent diabetes, Faisalabad histiocytosis and Familial Rosai–Dorfman disease (RDD). Herein, we report five new patients from a single family who present with phenotypes that associate features of H syndrome and Familial Rosai–Dorfman disease.MethodsWe investigated the clinical, biochemical, histopathological and molecular findings in five Tunisian family members' diagnosed with Familial RDD and/or H syndrome. The solute carrier family 29 (nucleoside transporters), member 3 (SLC29A3) gene was screened for molecular diagnosis using direct Sanger sequencing.ResultsGenetic analysis of all affected individuals revealed a previously reported missense mutation c.1088 G > A [p.Arg363Gln] in exon 6 of the SLC29A3 gene. Four affected members presented with clinical features consistent with the classical H syndrome phenotype. While their cousin’s features were in keeping with Familial Rosai–Dorfman disease diagnosis with a previously undescribed cutaneous RDD presenting as erythematous nodular plaques on the face. This report underlines the clinical variability of SLC29A3 disorders even with an identical mutation in the same family.ConclusionWe report a rare event of 5 Tunisian family members' found to be homozygous for SLC29A3 gene mutations but showing a different phenotype severity. Our study reveals that despite a single mutation, the clinical expression of the SLC29A3 disorders may be significantly heterogeneous suggesting a poor genotype–phenotype correlation for the disease.

GRIN2A Variants Associated With Idiopathic Generalized Epilepsies.

Objective: The objective of this study is to explore the role of GRIN2A gene in idiopathic generalized epilepsies and the potential underlying mechanism for phenotypic variation.Methods: Whole-exome sequencing was performed in a cohort of 88 patients with idiopathic generalized epilepsies. Electro-physiological alterations of the recombinant N-methyl-D-aspartate receptors (NMDARs) containing GluN2A mutants were examined using two-electrode voltage-clamp recordings. The alterations of protein expression were detected by immunofluorescence staining and biotinylation. Previous studies reported that epilepsy related GRIN2A missense mutations were reviewed. The correlation among phenotypes, functional alterations, and molecular locations was analyzed.Results: Three novel heterozygous missense GRIN2A mutations (c.1770A > C/p.K590N, c.2636A > G/p.K879R, and c.3199C > T/p.R1067W) were identified in three unrelated cases. Electrophysiological analysis demonstrated R1067W significantly increased the current density of GluN1/GluN2A NMDARs. Immunofluorescence staining indicated GluN2A mutants had abundant distribution in the membrane and cytoplasm. Western blotting showed the ratios of surface and total expression of the three GluN2A-mutants were significantly increased comparing to the wild type. Further analysis on the reported missense mutations demonstrated that mutations with severe gain-of-function were associated with epileptic encephalopathy, while mutations with mild gain of function were associated with mild phenotypes, suggesting a quantitative correlation between gain-of-function and phenotypic severity. The mutations located around transmembrane domains were more frequently associated with severe phenotypes and absence seizure-related mutations were mostly located in carboxyl-terminal domain, suggesting molecular sub-regional effects.Significance: This study revealed GRIN2A gene was potentially a candidate pathogenic gene of idiopathic generalized epilepsies. The functional quantitative correlation and the molecular sub-regional implication of mutations helped in explaining the relatively mild clinical phenotypes and incomplete penetrance associated with GRIN2A variants.

Structural characterization of clinically reported missense mutations identified in BRCA1

Structural characterization of clinically reported missense mutations identified in BRCA1

AHDC1 missense mutations in Xia-Gibbs syndrome.

SummaryXia-Gibbs syndrome (XGS; MIM: 615829) is a phenotypically heterogeneous neurodevelopmental disorder (NDD) caused by newly arising mutations in the AT-Hook DNA-Binding Motif-Containing 1 (AHDC1) gene that are predicted to lead to truncated AHDC1 protein synthesis. More than 270 individuals have been diagnosed with XGS worldwide. Despite the absence of an independent assay for AHDC1 protein function to corroborate potential functional consequences of rare variant genetic findings, there are also reports of individuals with XGS-like trait manifestations who have de novo missense AHDC1 mutations and who have been provided a molecular diagnosis of the disorder. To investigate a potential contribution of missense mutations to XGS, we mapped the missense mutations from 10 such individuals to the AHDC1 conserved protein domain structure and detailed the observed phenotypes. Five newly identified individuals were ascertained from a local XGS Registry, and an additional five were taken from external reports or databases, including one publication. Where clinical data were available, individuals with missense mutations all displayed phenotypes consistent with those observed in individuals with AHDC1 truncating mutations, including delayed motor milestones, intellectual disability (ID), hypotonia, and speech delay. A subset of the 10 reported missense mutations cluster in two regions of the AHDC1 protein with known conserved domains, likely representing functional motifs. Variants outside the clustered regions score lower for computational prediction of their likely damaging effects. Overall, de novo missense variants in AHDC1 are likely diagnostic of XGS when in silico analysis of their position relative to conserved regions is considered together with disease trait manifestations.

Novel Mutation and Deletion in SUN5 Cause Male Infertility with Acephalic Spermatozoa Syndrome

Acephalic spermatozoa syndrome (ASS) is a severe form of teratozoospermia, previous studies have shown that SUN5 mutations are the major cause of acephalic spermatozoa syndrome. This study is to identify the pathogenic mutations in SUN5 leading to ASS. PCR and Sanger sequence were performed to define the breakpoints and mutations in SUN5. Whole genome sequencing (WGS) was performed to detect heterozygous deletion. Western blotting and immunofluorescence analysis detected the expression level and localization of SUN5. Furthermore, the pathogenicity of the mutant SUN5 was predicted in silico and was verified by the experiments in vitro. We identified one novel homozygous missense mutation (c.775G>A; p.G259S) and one compound heterozygous including one reported missense mutation (c.1043A>T; p.N348I) and a large deletion that contains partial EFCAB8 ( NM_001143967 .1) and BPIFB2 ( NM_025227 ) and complete SUN5 ( NM_080675 ), and one recurrent homozygous splice-site mutation (c.340G>A; p.G114R) in SUN5 in three patients with ASS. Our results showed that SUN5 could not be detected in the patients' spermatozoa and the exogenous expression level of the mutant protein was decreased in transfected HEK-293T cells. This study expands the mutational spectrum of SUN5. We recommended a clinical diagnostic strategy for SUN5 genomic deletion to screen heterozygous deletions and indicated that the diagnostic value of screening for SUN5 mutations and deletions in infertile men with ASS.

Cardiac Arrest in a Child with Non-classic Lipoid Congenital Adrenal Hyperplasia Associated with a New STAR Gene Mutation

Abstract Introduction: Steroidogenic acute regulatory (STAR) protein regulates steroid hormone synthesis by transporting cholesterol into mitochondria. STAR gene mutations lead to lipoid congenital adrenal hyperplasia (LCAH), the rare but most severe form of congenital adrenal hyperplasia in children. We present an unusual case with an episode of cardiac arrest in a young girl during an acute febrile illness and later she was diagnosed with adrenal insufficiency secondary to a non-classic LCAH. Case: 2-year 11-month-old previously healthy white female was brought to an urgent care clinic due to severe lethargy and a seizure-like activity during a fever illness. She was found to have an undetectable blood glucose level and went into cardiac arrest shortly after arrival. CPR was performed for approximately 11 minutes. She then developed sever respiratory distress and was intubated. She was transferred to the PICU with IV sodium bicarbonate given en route. On admission, her body weight was 13.26 kg (36.80th percentile), height 90 cm (17.56th percentile), and BMI 16.17 (62.88th percentile). Her physical exam revealed normal external female genitalia and normal skin pigmentation. Lab evaluation revealed normal sodium and potassium but elevated anion gap, hyperuricemia, elevated creatinine kinase, abnormal liver function tests and abnormal coagulation profile. Brain MRI revealed findings consistent with hypoxic-ischemic encephalopathy. Renal function improved within 24 hours and hepatic function returned to normal after 20 days. Due to her severe hypoglycemic event, a high-dose ACTH stimulation test was performed. The results were consistent with adrenal insufficiency: baseline cortisol level, 7.3 μg/dL; 30 minutes cortisol, 7.8 μg/dL; 60 minutes cortisol, 9 μg/dL (normal response, ≥18 mcg/mL at 30 or 60 minutes). The baseline ACTH level was significantly elevated, 1688 pg/mL (0–46) as well as the renin activity, 24.3 ng/hour (1.7–11.2). Genetic testing revealed a 46 XX karyotype. STAR gene analysis identified compound heterozygosity; a novel deletion (c.811delC, p.Leu271Cysfs*50) and a previously reported missense mutation (c.661G>A, p.Gly221Ser). The girl is now 11 years old and exhibits normal growth, normal cognitive development, and she has developed early signs of puberty (Tanner stage 2 for breast). She takes daily hydrocortisone, fludrocortisone and stress dose hydrocortisone as needed. Conclusion: In non-classic LACH, the onset is generally late or not acute. Initial clinical features are variable and nonspecific. For this reason, non-classic LCAH may be overlooked. Adrenal crisis is a life-threatening complication, and it is important that clinicians are aware of the clinical features of non-classic LCAH and consider it in the differential diagnoses. Genetic testing for STAR should be considered in individuals with non-autoimmune primary adrenocortical insufficiency.

Megaconial congenital muscular dystrophy secondary to novel CHKB mutations resemble atypical Rett syndrome.

Megaconial congenital muscular dystrophy (CMD)(OMIM #602541), related to CHKB mutation, is a rare autosomal recessive disorder. To date, only 35 confirmed patients are recorded. We present a detailed description of the clinical, histopathological, imaging, and genetic findings of five children from four Indian families. The children had moderate-to-severe autistic behavior, hand stereotypies, and global developmental delay mimicking atypical Rett syndrome. In addition, generalized hypotonia was a common initial finding. The progression of muscle weakness was variable, with two patients having a milder phenotype and three having a severe form. Interestingly, the majority did not attain sphincter control. Only patient 1 had classical ichthyotic skin changes. Muscle biopsy in two patients showed a myopathic pattern with characteristic peripherally placed enlarged mitochondria on modified Gomori trichrome stain and electron microscopy. Genetic analysis in these patients identified three novel null mutations in CHKB [c.1027dupA (p.Ser343LysfsTer86);c.224 + 1G > T (5' splice site); c.1123C > T (p.Gln375Ter)] and one reported missense mutation, c.581G > A (p.Arg194Gln), all in the homozygous state. Megaconial CMD, although rare, forms an important group with a complex phenotypic presentation and accounted for 5.5% of our genetically confirmed CMD patients. Atypical Rett syndrome-like presentation may be a clue towards CHKB-related disorder.

FANCA Gene Mutations in North African Fanconi Anemia Patients.

Populations in North Africa (NA) are characterized by a high rate of consanguinity. Consequently, the proportion of founder mutations might be higher than expected and could be a major cause for the high prevalence of recessive genetic disorders like Fanconi anemia (FA). We report clinical, cytogenetic, and molecular characterization of FANCA in 29 North African FA patients from Tunisia, Libya, and Algeria. Cytogenetic tests revealed high rates of spontaneous chromosome breakages for all patients except two of them. FANCA molecular analysis was performed using three different molecular approaches which allowed us to identify causal mutations as homozygous or compound heterozygous forms. It included a nonsense mutation (c.2749C > T; p.Arg917Ter), one reported missense mutation (c.1304G > A; p.Arg435His), a novel missense variant (c.1258G > A; p.Asp409Glu), and the FANCA most common reported mutation (c.3788_3790delTCT; p.Phe1263del). Furthermore, three founder mutations were identified in 86.7% of the 22 Tunisian patients: (1) a deletion of exon 15, in 36.4% patients (8/22); (2), a deletion of exons 4 and 5 in 23% (5/22) and (3) an intronic mutation c.2222 + 166G > A, in 27.3% (6/22). Despite the relatively small number of patients studied, our results depict the mutational landscape of FA among NA populations and it should be taken into consideration for appropriate genetic counseling.