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Novel compound heterozygous stop-gain mutations of LRBA in a Vietnamese patient with Common Variable Immune Deficiency.

ABSTRACT: BACKGROUND:Lipopolysaccharide-responsive and beige-like anchor (LRBA) deficiency is a rare autosomal recessive common variable immunodeficiency (CVID), affecting 1:25,000-1:50,000 people worldwide. Biallelic mutations in the gene LRBA have been implicated in affected individuals. METHODS:We report a 16-year-old Vietnamese, male patient with recurrent CVID symptoms including chronic diarrhea, interstitial pneumonia, cutaneous granulomatous lesions, hepatosplenomegaly, and finger clubbing. Immunological analyses and whole exome sequencing (WES) were performed to investigate phenotypic and genotypic features. RESULTS:Immunological analyses revealed hypogammaglobulinemia and low ratios of CD4+/CD8+ T cells. Two novel compound heterozygous stop-gain mutation in LRBA were identified: c.1933C > T (p.R645X) and c.949C > T (p.R317X). Sanger sequencing confirmed the segregation of these variants from the intact parents. The abolished LRBA protein expression was shown by immunoblot analysis. Subsequent treatment potentially saves the child from the same immune thrombocytopenia which led to his brother's untimely death; likely caused by the same LRBA mutations. CONCLUSION:This first report of LRBA deficiency in Vietnam expands our knowledge of the diverse phenotypes and genotypes driving CVID. Finally, the utilization of WES shows great promise as an effective diagnostic for CVID in our setting.

SUBMITTER: Phan ANL

PROVIDER: S-EPMC7216813 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

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Novel compound heterozygous stop-gain mutations of LRBA in a Vietnamese patient with Common Variable Immune Deficiency.

Phan Anh N L ANL Pham Thuy T T TTT Huynh Nghia N Nguyen Tuan M TM Cao Cuc T T CTT Nguyen Duong T DT Le Duc T DT Bui Chi-Bao CB

Molecular genetics & genomic medicine 20200310 5

<h4>Background</h4>Lipopolysaccharide-responsive and beige-like anchor (LRBA) deficiency is a rare autosomal recessive common variable immunodeficiency (CVID), affecting 1:25,000-1:50,000 people worldwide. Biallelic mutations in the gene LRBA have been implicated in affected individuals.<h4>Methods</h4>We report a 16-year-old Vietnamese, male patient with recurrent CVID symptoms including chronic diarrhea, interstitial pneumonia, cutaneous granulomatous lesions, hepatosplenomegaly, and finger cl ...[more]

PMID: 32154999

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Project description:Background: Ornithine transcarbamylase deficiency (OTCD) is an X- linked recessive disorder and the most common error of the urea cycle, caused by the mutations in the OTC gene. Due to X-inactivation, 15-20% of female carriers present symptoms of OTCD at late onset. Early diagnosis of OTCD by molecular analysis in females is highly desirable. The aim of the study was to identify the mutations in two unrelated Vietnamese girls suspected with OTCD and the carriers in their families for definitive diagnosis and proper counseling. Case Presentation: Two patients presented with an acute encephalopathy at the first admission. Biochemical tests revealed hyperammonemia, hyperlactatemia, elevated glutamine level, elevated transaminase, elevated urinary orotic and uracil acid levels, and disorder of prothrombin time. Brain magnetic resonance imaging indicated cerebral edema. Based on the clinical and laboratory results, the two patients were diagnosed with urea cycle disorders. Therefore, the two patients were managed by stopping feeding, with infused glucose, l-carnitine, l-arginine, and sodium benzoate, and with hemofiltration. The two patients were alert and recovered with normal blood ammonia levels after 72 h of treatment. The family history of patient 1 showed that her brother died at 4 days of age due to a coma and dyspnea, while her parents were asymptomatic. Variable phenotypes were observed in three generations of the patient 2's family, including asymptomatic (mother), affected female adults dying at the first symptom (grandmother and aunt), and affected males dying in the first week of life (uncle, cousin, and siblings). Whole-exome sequencing showed two mutations in the OTC gene, including one novel missense mutation, c.365A>T, in the patient 1 and one previously reported splicing mutation, c.717+1G>A, in the patient 2. The two mutations are evaluated as likely pathogenic and pathogenic, respectively, according to the recommendations of the American College of Medical Genetics and Genomics (ACMG). Genetic analyses in the families indicated the mothers were heterozygous. Conclusion: Clinical, biochemical, and molecular findings accurately diagnosed the two patients with late-onset OTCD. Our results explained the genetic causes and proposed the risk in the patients' families, which could be useful for genetic counseling and monitoring in prenatal diagnosis.

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Dataset Information

Novel compound heterozygous stop-gain mutations of LRBA in a Vietnamese patient with Common Variable Immune Deficiency.

Publications

Novel compound heterozygous stop-gain mutations of LRBA in a Vietnamese patient with Common Variable Immune Deficiency.

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