Novel Mitochondrial Cytopathy Causing Mitochondrial Encephalomyopathy With Lactic Acidosis and Stroke-Like Episodes Syndrome and Tubulointerstitial Nephropathy.

Mitochondrial cytopathies, predominantly MT-TL1 mutations and, to a lesser extent, MT-ND5, have been associated with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), manifesting as multi-organ dysfunction. This is just the second instance of MELAS secondary to the pathogenic novel m.13091T>C variant of MT-ND5. Moreover, nephropathy associated with MT-ND5 mutation has only been reported in nine cases so far. A middle-aged man presented in a state of acute confusion with speech difficulty with both receptive and expressive aphasia. He had a background of refractory seizures, chronic atypical migraine, childhood-onset optic neuropathy, and end-stage renal disease requiring renal transplant. During admission, he had episodes of aggression and paranoid beliefs. Magnetic resonance (MR) imaging of the head showed multiple areas of cortical abnormality, unusual for age, including a large frontal infarct crossing arterial boundaries. Cerebrospinal fluid (CSF) protein and lactate were high, whereas, the electroencephalography (EEG) result was normal. Muscle biopsy mitochondrial DNA gene sequencing derived novel MT-ND5 gene variant m.13091T>C p.(Met252Thr). Kidney biopsy previously had shown interstitial fibrosis and tubular atrophy. He was managed as acute ischaemic stroke along with a combination of clobazam, levetiracetam, and eslicarbazepine for seizures. MELAS typically presents with seizures, stroke-like episodes, cortical visual loss, and recurrent migraine headaches. The previous reported case of m.13091T>C mutation followed a similar progression, however, there was no associated nephropathy and normal visual acuity. Kidney transplants in affected patients of MELAS have been associated with a high survival rate. MT-ND5 mutation-associated nephropathy has shown a variable manifestation, either as focal segmental glomerular sclerosis (FSGS) or tubulo-interstitial disease.

Active spread of ß-thalassemia beyond the thalassemia belt: A study on a Russian population.

ß-Thalassemia is a disease traditionally associated with thalassemia belt countries. Nonetheless, as global migration intensifies, ß-thalassemia-causing variants spread far from their origin. We investigated this process to detect some patterns underlying its course. We analyzed ß-thalassemia-causing variants and the origin of 676 unrelated participants in Moscow, the largest city of Russia, far away from the thalassemia belt. Our analyses revealed that modern Russia has one of the broadest spectra of thalassemia-causing variants: 46 different variants, including two novel ß0 variants. Only a small proportion of the reported pathogenic variants likely originated in the resident subpopulation. Almost half of the variants that supposedly had emerged outside the Russian borders have already been assimilated by (were found in) the resident subpopulation. The primary modern source of immigration transferring thalassemia to a nonthalassemic part of Russia is the Caucasus region. We also found traces of ancient migration flows from non-Caucasus countries. Our data indicate that ß-thalassemia-causing variants are actively spilling over into resident populations of countries outside thalassemia belt regions. Therefore, viewing thalassemia as a disease exclusive to specific ethnic groups creates a mind trap that can complicate the diagnosis.

A novel start-loss mutation of the SLC29A3 gene in a consanguineous family with H syndrome: clinical characteristics, in silico analysis and literature review.

BACKGROUND: The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene. METHODS: In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing. RESULTS: In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein. CONCLUSION: Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition.

Identification of a novel mutation of the FLT3 gene located on the juxtamembrane domain from acute myeloid leukemia patients.

BACKGROUND: FLT3 gene mutations are genetic abnormality that caused leukemogenesis. Furthermore, presence of FLT3 mutations is associated with poor prognosis in AML. This study aimed to identify FLT3 gene mutations so that it can be used as a genetic reference for the AML patients in Indonesian population. METHODS: This cross-sectional study recruited 63 AML de novo patients between August 2021 and July 2023 at Cipto Mangukusumo General Hospital and Dharmais Cancer Hospital. We collected peripheral blood from the patients for DNA isolation. FLT3 gene mutation was detected using PCR method, then followed by the Sanger sequencing. Novel mutation in exon-14 continued to in silico study using SWISS MODEL server for modelling protein and PyMOL2 software for visualizing the protein model. RESULTS: Frequency FLT3-ITD mutation was 22% and 6 (10%) patients had a novel mutation on juxtamembrane domain. The number of FLT3-ITD insertions was 24 bp to 111 bp, with a median of 72 bp. Novel mutation indicated a change in the protein sequence at amino acid number 572 from Tyrosine to Valine and formed a stop codon (UGA) at amino acid position ins572G573. In-silico study from novel mutation showed the receptor FLT3 protein was a loss of most of the juxtamembrane domain and the entire kinase domain. CONCLUSION: A novel FLT3 gene mutation was found in this study in the juxtamembrane domain. Based on the sequencing analysis and in silico studies, this mutation is likely to affect the activity of the FLT3 receptor. Therefore, further studies on this novel mutation are needed.

A novel case report of benign recurrent intrahepatic cholestasis-associated USP53 genetic mutation in a Pakistani girl.

Benign recurrent intrahepatic cholestasis is an autosomal recessive disorder presenting with intermittent episodes of cholestatic jaundice. The initial episode of benign recurrent intrahepatic cholestasis tends to occur within the first two decades of a patient's life. Episodes can occur unprompted but can often be precipitated by infections or pregnancy. We report an interesting case of a 13-year-old girl presented with recurrent intrahepatic cholestasis. The patient has a unique homozygous USP53 genetic mutation, the first patient to present with this mutation within the South Asian region. The patient was initially misdiagnosed as a case of autoimmune hepatitis, and when presenting to our set-up was diagnosed as a case of benign recurrent intrahepatic cholestasis. The patient has since been managed on medication and remains regular in follow-up, responding well to treatment.

A novel splice-altering TNC variant (c.5247A > T, p.Gly1749Gly) in an Chinese family with autosomal dominant non-syndromic hearing loss.

BACKGROUND: This study aims to analyze the pathogenic gene in a Chinese family with non-syndromic hearing loss and identify a novel mutation site in the TNC gene. METHODS: A five-generation Chinese family from Anhui Province, presenting with autosomal dominant non-syndromic hearing loss, was recruited for this study. By analyzing the family history, conducting clinical examinations, and performing genetic analysis, we have thoroughly investigated potential pathogenic factors in this family. The peripheral blood samples were obtained from 20 family members, and the pathogenic genes were identified through whole exome sequencing. Subsequently, the mutation of gene locus was confirmed using Sanger sequencing. The conservation of TNC mutation sites was assessed using Clustal Omega software. We utilized functional prediction software including dbscSNV_AdaBoost, dbscSNV_RandomForest, NNSplice, NetGene2, and Mutation Taster to accurately predict the pathogenicity of these mutations. Furthermore, exon deletions were validated through RT-PCR analysis. RESULTS: The family exhibited autosomal dominant, progressive, post-lingual, non-syndromic hearing loss. A novel synonymous variant (c.5247A > T, p.Gly1749Gly) in TNC was identified in affected members. This variant is situated at the exon-intron junction boundary towards the end of exon 18. Notably, glycine residue at position 1749 is highly conserved across various species. Bioinformatics analysis indicates that this synonymous mutation leads to the disruption of the 5' end donor splicing site in the 18th intron of the TNC gene. Meanwhile, verification experiments have demonstrated that this synonymous mutation disrupts the splicing process of exon 18, leading to complete exon 18 skipping and direct splicing between exons 17 and 19. CONCLUSION: This novel splice-altering variant (c.5247A > T, p.Gly1749Gly) in exon 18 of the TNC gene disrupts normal gene splicing and causes hearing loss among HBD families.

Woodhouse-Sakati Syndrome: The New Genetic Variant of DCAF17 In 2 Adult Sisters.

Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive disorder associated with progressive extrapyramidal signs, mental retardation, alopecia, and a variety of endocrine deficiencies, including diabetes mellitus, hypogonadism, and hypothyroidism. To date, approximately 98 genetically confirmed WSS families have been reported worldwide. This report focuses on a new genetic variant detected in 2 WSS-affected sisters with distinctive phenotypical features. The case under review is of special interest due to the multiple manifestations of WSS. This is the first family case of WSS identified in the Russian Federation. Although there is no specific treatment for WSS, genetic testing makes it possible to diagnose WSS, make a prognosis, and provide comprehensive patient-oriented treatment.

Two novel compound heterozygous loss-of-function mutations cause fetal IRAK-4 deficiency presenting with Pseudomonas Aeruginosa sepsis.

PURPOSE: To report a case of a five-month-old Chinese infant who died of interleukin-1 receptor-associated kinase-4 (IRAK-4) deficiency presenting with rapid and progressive Pseudomonas aeruginosa sepsis. METHODS: The genetic etiology of IRAK-4 deficiency was confirmed through trio-whole exome sequencing and Sanger sequencing. Functional consequences were invested using an in vitro minigene splicing assay. RESULTS: Trio-whole exome sequencing of genomic DNA identified two novel compound heterozygous mutations, IRAK-4 (NM_016123.3): c.942-1G > A and c.644_651+ 6delTTGCAGCAGTAAGT in the proband, which originated from his symptom-free parents. These mutations were predicted to cause frameshifts and generate three truncated proteins without enzyme activity. CONCLUSIONS: Our findings expand the range of IRAK-4 mutations and provide functional support for the pathogenic effects of splice-site mutations. Additionally, this case highlights the importance of considering the underlying genetic defects of immunity when dealing with unusually overwhelming infections in previously healthy children and emphasizes the necessity for timely treatment with wide-spectrum antimicrobials.

Molecular genetics, neuroimaging outcomes, and structural analyses of novel and recurrent variants of WDR62 gene in two consanguineous Pakistani families with autosomal recessive primary microcephaly.

BACKGROUND: Autosomal recessive primary microcephaly (MCPH) is a rare neurodevelopmental and genetically heterogeneous disorder, characterized by small cranium size (> - 3 SD below mean) and often results in varying degree of intellectual disability. Thirty genes have been identified for the etiology of this disorder due to its clinical and genetic heterogeneity. METHODS AND RESULTS: Here, we report two consanguineous Pakistani families affected with MCPH exhibiting mutation in WDR62 gene. The investigation approach involved Next Generation Sequencing (NGS) gene panel sequencing coupled with linkage analysis followed by validation of identified variants through automated Sanger sequencing and Barcode-Tagged (BT) sequencing. The molecular genetic analysis revealed one novel splice site variant (NM_001083961.2(WDR62):c.1372-1del) in Family A and one known exonic variant NM_001083961.2(WDR62):c.3936dup (p.Val1313Argfs*18) in Family B. Magnetic Resonance Imaging (MRI) scans were also employed to gain insights into the structural architecture of affected individuals. Neurological assessments showed the reduced gyral and sulcal patterns along with normal corpus callosum in affected individuals harboring novel variant. In silico assessments of the identified variants were conducted using different tools to confirm the pathogenicity of these variants. Through In silico analyses, both variants were identified as disease causing and protein modeling of exonic variant indicates subtle conformational alterations in prophesied protein structure. CONCLUSION: This study identifies a novel variant (c.1372-1del) and a recurrent pathogenic variant c.3936dup (p.Val1313Argfs*18) in the WDR62 gene among the Pakistani population, expanding the mutation spectrum for MCPH. These findings emphasize the importance of genetic counseling and awareness to reduce consanguinity and address the burden of this disorder.

Identification of a Novel Homozygous Mutation in MTMR2 Gene Causes Very Rare Charcot-Marie-Tooth Disease Type 4B1.

Background: Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders involving peripheral nervous system. Charcot-Marie-Tooth disease 4B1 (CMT4B1) is a rare subtype of CMT. CMT4B1 is an axonal demyelinating polyneuropathy with an autosomal recessive mode of inheritance. Patients with CMT4B1 usually manifested with dysfunction of the motor and sensory systems which leads to gradual and progressive muscular weakness and atrophy, starting from the peroneal muscles and finally affecting the distal muscles. Germline mutations in MTMR2 gene causes CMT4B1. Material and Methods: In this study, we investigated a 4-year-old Chinese boy with gradual and progressive weakness and atrophy of both proximal and distal muscles. The proband's parents did not show any abnormalities. Whole-exome sequencing and Sanger sequencing were performed. Results: Whole-exome sequencing identified a novel homozygous nonsense mutation (c.118A>T; p.Lys40*) in exon 2 of MTMR2 gene in the proband. This novel mutation leads to the formation of a truncated MTMR2 protein of 39 amino acids instead of the wild- type MTMR2 protein of 643 amino acids. This mutation is predicted to cause the complete loss of the PH-GRAM domain, phosphatase domain, coiled-coil domain, and PDZ-binding motif of the MTMR2 protein. Sanger sequencing revealed that the proband's parents carried the mutation in a heterozygous state. This mutation was absent in 100 healthy control individuals. Conclusion: This study reports the first mutation in MTMR2 associated with CMT4B1 in a Chinese population. Our study also showed the importance of whole-exome sequencing in identifying candidate genes and disease-causing variants in patients with CMT4B1.

Novel Mutation in the HSD17B10 Gene Accompanied by Dysmorphic Findings in Female Patients.

Introduction: Hydroxysteroid 17-beta dehydrogenase type 10 (HSD10) protein is a mitochondrial enzyme. Multisystemic involvement occurs in HSD10 deficiency as in other mitochondrial diseases. HSD10 deficiency (disease) is rare. Less than 40 index cases have been reported so far. A female patient is even rarer because of X-linked transmission. Five index female cases have been reported. Case Presentation: We report a three-year-old female patient who was investigated due to microcephaly and global developmental delay. She had significant dysmorphic findings. The tiglylglycine peak was detected in urinary organic acid analysis. Other metabolic investigations and laboratory tests were unremarkable. Mild cerebral atrophy, mild ventricular dilation, thin corpus callosum, and an increase in T2 signal in the globus pallidus were revealed at brain magnetic resonance imaging. Heterozygous novel mutation in the HSD17B10 gene was found by whole-exome sequencing (WES) analysis. We started isoleucine-restricted diet and a "cocktail" of the mitochondrial vitamin. Discussion/Conclusion: We will see HSD10 disease patients more frequently with the increasing use of WES and genetic panels. Thus, different findings and phenotypes of the HSD10 disease will be revealed.

The Research of a Large-Scale Analysis Platform for MNS Blood Group Identification Based on Long-Read Sequencing.

The objective of this study was to devise a novel approach for determining MNS blood group utilizing long-read sequencing (LRS) and to identify intricate genome variations associated with this blood group system. In this study, a total of 60 blood samples were collected from randomly selected Chinese Han blood donors. The amplification of the full-length sequences of GYPA exon 2-7 (11 kb) and GYPB exon 2-6 (7 kb) was conducted on the blood samples obtained from these 60 donors. Subsequently, the sequencing of these amplified sequences was performed using the PacBio platform. The obtained sequencing data were then compared with the reference sequence of the human genome (GRCh38) utilizing the pbmm2 software, resulting in the acquisition of the haploid sequences of GYPA and GYPB. The serological typing prediction was conducted using the International Society of Blood Transfusion (ISBT) database, while the analysis of SNVs sites was performed using deepvariant v1.2.0 software and reference sequence alignment. A total of 60 samples yielded unambiguous high-quality haplotypes, which can serve as a standardized reference sequence for molecular biology typing of MNSs in the Chinese population. In a total of 60 serological samples, the LRS method successfully identified the M, N, S, and s blood group antigens by analyzing specific genetic variations (c.59, c.71, c.72 for GYPA, and c.143 for GYPB), which aligned with the results obtained through conventional serological techniques. 4 Mur samples that had been previously validated through serology and molecular biology were successfully confirmed, and complete haploid sequences were obtained. Notably, one of the Mur samples exhibited a novel breakpoint, GYP (B1-136-B ψ 137-212-A213-229-B230-366), thereby representing a newly identified subtype. Single molecule sequencing, which eliminates the necessity for PCR amplification, effectively encompasses GC and high repeat regions, enhancing accuracy in quantifying mutations with low abundance or frequency. By employing LRS analysis of the core region of GYPA and GYPB, diverse genotypes of MNS can be precisely and reliably identified in a single assay. This approach presents a comprehensive, expeditious, and precise novel method for the categorization and investigation of MNS blood group system.

Genotype-phenotype correlations of AR-CMT2S in a cohort of axonal Charcot-Marie-Tooth patients from Central South China.

BACKGROUND AND AIMS: This study aimed to report nine Charcot-Marie-Tooth disease (CMT) families with six novel IGHMBP2 mutations in our CMT2 cohort and to summarize the genetic and clinical features of all AR-CMT2S patients reported worldwide. METHODS: General information, clinical and neurophysiological data of 275 axonal CMT families were collected. Genetic screening was performed by inherited peripheral neuropathy related genes panel or whole exome sequencing. The published papers reporting AR-CMT2S from 2014 to 2023 were searched in Pubmed and Wanfang databases. RESULTS: In our CMT2 cohort, we detected 17 AR-CMT2S families carrying IGHMBP2 mutations and eight were published previously. Among these, c.743 T > A (p.Val248Glu), c.884A > G (p.Asp295Gly), c.1256C > A (p.Ser419*), c.2598_2599delGA (p.Lys868Sfs*16), c.1694_1696delATG (p.Asp565del) and c.2509A > T (p.Arg837*) were firstly reported. These patients prominently presented with early-onset typical axonal neuropathy and without respiratory dysfunction. So far, 56 AR-CMT2S patients and 57 different mutations coming from 43 families have been reported in the world. Twenty-nine of 32 missense mutations were clustered in helicase domain and ATPase region. The age at onset ranged from 0.11to 20 years (Mean ± SD: 3.43 ± 3.88 years) and the majority was infantile-onset (<2 years). The initial symptoms included weakness of limbs (19, 29.7%), delayed milestones (12, 18.8%), gait disturbance (11, 17.2%), feet deformity (8, 12.5%), feet drop (8, 12.5%), etc. INTERPRETATION: AR-CMT2S accounted for 6.2% in our CMT2 cohort. We firstly reported six novel IGHMBP2 mutations which expanded the genotypic spectrum of AR-CMT2S. Furthermore, 17 AR-CMT2S families could provide more resources for natural history study, drug research and development.

A novel mutation in ANOS1 in a Chinese family with Kallmann syndrome: Case report.

We reported a novel variant in Kallmann syndrome. It not only determines the clinical importance of whole exome sequencing for identification of genetic pathogenic variants, but also enriches the ANOS1 genetic spectrum of CHH patients in Chinese population.

CD21 deficiency in 2 siblings and frequency of the associated mutation in the Danish population.

The clinical presentation of CD21 deficiency in 2 siblings caused by a novel mutation in the CD21 gene is reported, and the frequency of this mutation in the Danish population is explored. Successful treatment with IgG replacement in both patients with CD21 deficiency is also reported.

A novel homozygous RSPH4A variant in a family with primary ciliary dyskinesia and literature review.

Introduction: Primary ciliary dyskinesia (PCD) is a rare heterogeneous disease caused by abnormalities in motile cilia. In this case report, we first analyzed the clinical and genetic data of a proband who was suspected of having PCD on the basis of her clinical and radiological findings. Methods: Whole-exome sequencing was performed, and a variant in the RSPH4A gene was identified in the proband. Sanger sequencing was used for validation of RSPH4A variants in the proband, her sister, her daughter and her parents. Finally, the phenotypic features of the patient were analyzed, and the current literature was reviewed to better understand the gene variants in PCD related to hearing loss and the clinical manifestations of the RSPH4A variant in PCD. Results: The chief clinical symptoms of this proband included gradual mixed hearing loss, otitis media, anosmia, sinusitis, recurrent cough and infertility. Her DNA sequencing revealed a novel homozygous T to C transition at position 1321 within exon 3 of RSPH4A according to genetic testing results. This variant had never been reported before. The homozygous variant resulted in an amino acid substitution of tryptophan by arginine at position 441 (p.Trp441Arg). The same variant was also found in the proband's sister, and a heterozygous pathogenic variant was identified among immediate family members, including the proband's daughter and parents. Discussion: A literature review showed that 16 pathogenic variants in RSPH4A have been reported. Hearing loss had only been observed in patients with the RSPH4A (c.921+3_6delAAGT) splice site mutation, and the specific type of hearing loss was not described.

Biochemical and molecular analysis of pediatric patients with metachromatic leukodystrophy in South China: functional characterization of five novel ARSA variants.

Metachromatic leukodystrophy (MLD) is a rare hereditary neurodegenerative disease caused by deficiency of the lysosomal enzyme arylsulfatase A (ARSA). This study described the clinical and molecular characteristics of 24 Chinese children with MLD and investigated functional characterization of five novel ARSA variants. A retrospective analysis was performed in 24 patients diagnosed with MLD at Guangzhou Women and Children's Medical Center in South China. Five novel mutations were further characterized by transient expression studies. We recruited 17 late-infantile, 3 early-juvenile, 4 late-juvenile MLD patients. In late-infantile patients, motor developmental delay and gait disturbance were the most frequent symptoms at onset. In juvenile patients, cognitive regression and gait disturbance were the most frequent chief complaints. Overall, 25 different ARSA mutations were identified with 5 novel mutations.The most frequent alleles were p.W320* and p.G449Rfs. The mutation p.W320*, p.Q155=, p.P91L, p.G156D, p.H208Mfs*46 and p.G449Rfs may link to late-infantile type. The novel missense mutations were predicted damaging in silico. The bioinformatic structural analysis of the novel missense mutations showed that these amino acid replacements would cause severe impairment of protein structure and function. In vitro functional analysis of the six mutants, showing a low ARSA enzyme activity, clearly demonstrated their pathogenic nature. The mutation p.D413N linked to R alleles. In western blotting analysis of the ARSA protein, the examined mutations retained reduced amounts of ARSA protein compared to the wild type. This study expands the spectrum of genotype of MLD. It helps to the future studies of genotype-phenotype correlations to estimate prognosis and develop new therapeutic approach.

Primary immune regulatory disorders (PIRD): expanding the mutation spectrum in Turkey and identification of sixteen novel variants.

Human Inborn Errors of Immunity (IEIs) encompass a clinically and genetically heterogeneous group of disorders, ranging from mild cases to severe, life-threatening types. Among these, Primary Immune Regulatory Disorders (PIRDs) constitute a subset of IEIs characterized by diverse clinical phenotypes, prominently featuring severe atopy, autoimmunity, lymphoproliferation, hyperinflammation, autoinflammation, and susceptibility to malignancies. According to the latest report from the International Union of Immunological Societies (IUIS), PIRDs arise from mutations in various genes including LYST, RAB27A, AP3B1, AP3D1, PRF1, UNC13D, STX11, STXBP2, FAAP24, SLC7A7, RASGRP1, CD70, CTPS1, RLTPR, ITK, MAGT1, PRKCD, TNFRSF9, SH2DIA, XIAP, CD27 (TNFRSF7), FAS (TNFRSF6), FASLG (TNFSF6), CASP10, CASP8, FADD, LRBA, STAT3, AIRE, ITCH, ZAP70, TPP2, JAK1, PEPD, FOXP3, IL2RA, CTLA4, BACH2, IL2RB, DEF6, FERMT1, IL10, IL10RA, IL10RB, NFAT5, TGFB1, and RIPK1 genes. We designed a targeted next-generation sequencing (TNGS) workflow using the Ion AmpliSeq™ Primary Immune Deficiency Research Panel to sequence 264 genes associated with IEIs on the Ion S5™ Sequencer. In this study, we report the identification of 38 disease-causing variants, including 16 novel ones, detected in 40 patients across 15 distinct PIRD genes. The application of next-generation sequencing enabled rapid and precise diagnosis of patients with PIRDs.

[A pedigree of myotonia congenita with a novel mutation p.F343C of the CLCN1 gene].

A Japanese woman experienced slowness of movement in her early teens and difficulty in opening her hands during pregnancy. On admission to our hospital at 42 years of age, she showed grip myotonia with warm-up phenomenon. However, she had neither muscle weakness, muscle atrophy, cold-induced symptomatic worsening nor episodes of transient weakness of the extremities. Needle electromyography of the first dorsal interosseous and anterior tibial muscles demonstrated myotonic discharges. Whole exome sequencing of the patient revealed a heterozygous single-base substitution in the CLCN1 gene (c.1028T>G, p.F343C). The same substitution was identified in affected members of her family (mother and brother) by Sanger sequencing, but not in healthy family members (father and a different brother). We diagnosed myotonia congenita (Thomsen disease) with a novel CLCN1 mutation in this pedigree. This mutation causes a single amino acid substitution in the I-J extracellular loop region of CLCN1. Amino acid changes in the I-J loop region are rare in an autosomal-dominantly inherited form of myotonia congenita. We think that this pedigree is precious to understand the pathogenesis of myotonia congenita.