Search

Summary Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous distal symmetric polyneuropathy. Whole-exome sequencing (WES) of 40 individuals from 37 unrelated families with CMT-like peripheral neuropathy refractory to molecular diagnosis identified apparent causal mutations in ∼45% (17/37) of families. Three candidate disease genes are proposed, supported by a combination of genetic and in vivo studies. Aggregate analysis of mutation data revealed a significantly increased number of rare variants across 58 neuropathy-associated genes in subjects versus controls, confirmed in a second ethnically discrete neuropathy cohort, suggesting that mutation burden potentially contributes to phenotypic variability. Neuropathy genes shown to have highly penetrant Mendelizing variants (HPMVs) and implicated by burden in families were shown to interact genetically in a zebrafish assay exacerbating the phenotype established by the suppression of single genes. Our findings suggest that the combinatorial effect of rare variants contributes to disease burden and variable expressivity. [ABSTRACT FROM AUTHOR]

Abstract: Protein tyrosine kinases (PTKs) play an important role in T cell development and activation. In vitro and in vivo defects, resulting in variable deficiencies in thymic development and in T cell antigen receptor (TCR) signal transduction, in PTKs have been shown. ZAP70, one of those PTKs, is a 70-kDa tyrosine phosphoprotein and associates with the ζ chain and undergoes tyrosine phosphorylation following TCR stimulation. It is expressed in T and natural killer (NK) cells. Several mutations were shown to lead to an autosomal recessive form of severe combined immunodeficiency disease (SCID). Here, we present a family with a novel mutation in ZAP70. The proband, the second child of the first cousin parents of Turkish origin, was diagnosed with SCID having R514C mutation on homozygous state. She had decreased CD8+ T and natural killer cells, normal CD4+ T cells, high serum Ig E level, perivascular dermatitis and ichthyosis. This article presents clinical features of a novel mutation on ZAP70 and the first prenatal molecular diagnosis of ZAP70 deficiency. Different mutations in ZAP70 and related phenotypes reported in the literature are also discussed. [Copyright &y& Elsevier]

Three brothers, born to parents who were first cousins, were referred for progressive diffuse dystonia. Initial physical examinations revealed minor dysmorphic features, e.g., bifrontal narrowing, downslanting palpebral fissures, low-set ears, upturned nostrils, and microretrognathia, as well as neurodevelopmental delay. Absence of eye contact and head control, diffuse dystonia, hypokinesia, choreoathetosis, tremor, increased deep tendon reflexes, diffuse muscle atrophy, and spasticity were evident during neurologic evaluations. After laboratory investigations, imaging studies, and the exclusion of other causes of childhood dystonia, the children were diagnosed with Segawa syndrome. A molecular analysis of the tyrosine hydroxylase gene revealed a novel P492R (1475 C>G) mutation, further confirming the clinical diagnosis. After 1-month therapy with 2 mg/kg/day l-dopa, no changes in signs were evident. Selegiline was added, which greatly improved the clinical picture. Segawa syndrome in three brothers resulted from a novel mutation in the tyrosine hydroxylase gene. Treatment with a combination of l-dopa and selegiline led to favorable outcomes. [Copyright &y& Elsevier]

Abstract: Background: 46,XY, or Swyer syndrome, is a complete gonadal dysgenesis. Patients usually presents with primary amenorrhea with underdeveloped secondary sex characteristics. Phenotypes of these patients are female. In this report, a Swyer syndrome case is reported with novel clinical features that are classified as connective tissue disorders. This case and the 2 other previously reported Swyer syndrome cases with ascendant aortic aneurysm and diaphragmatic hernia are suggest that the Y chromosome has an important role in the structure of connective tissue. Case: Here we report a case of a 17-year-old with clinical features of 46,XY complete gonadal dysgenesis including external female genitalia, hypoplastic uterus, hypergonadotrophic hypogonadism, incomplete secondary sex characterics, primary amenorrhea, and normal male karyotype. In addition, she had mild mental retardation, severe rotoscoliosis, pectus excavatus, spina bifida occulta, hip dislocation, and long, slender extremities. She had a rudimentary uterus and streak gonads; after giving her cyclic estrogen and progesterone pills, she was able to menstruate. Summary and Conclusion: In this report, a Swyer syndrome case was discussed regarding clinical features, especially those are not characteristic for Swyer syndrome after a review of the literature. [Copyright &y& Elsevier]

Objective To investigate the genetic cause of nonobstructive azoospermia (NOA) in a consanguineous Turkish family through homozygosity mapping followed by targeted exon/whole-exome sequencing to identify genetic variations. Design Whole-exome sequencing (WES). Setting Research laboratory. Patient(s) Two siblings in a consanguineous family with NOA. Intervention(s) Validating all variants passing filter criteria with Sanger sequencing to confirm familial segregation and absence in the control population. Main Outcome Measure(s) Discovery of a mutation that could potentially cause NOA. Result(s) A novel nonsynonymous mutation in the neuronal PAS-2 domain ( NPAS2 ) was identified in a consanguineous family from Turkey. This mutation in exon 14 (chr2: 101592000 C>G) of NPAS2 is likely a disease-causing mutation as it is predicted to be damaging, it is a novel variant, and it segregates with the disease. Family segregation of the variants showed the presence of the homozygous mutation in the three brothers with NOA and a heterozygous mutation in the mother as well as one brother and one sister who were both fertile. The mutation is not found in the single-nucleotide polymorphism database, the 1000 Genomes Project, the Baylor College of Medicine cohort of 500 Turkish patients (not a population-specific polymorphism), or the matching 50 fertile controls. Conclusion(s) With the use of WES we identified a novel homozygous mutation in NPAS2 as a likely disease-causing variant in a Turkish family diagnosed with NOA. Our data reinforce the clinical role of WES in the molecular diagnosis of highly heterogeneous genetic diseases for which conventional genetic approaches have previously failed to find a molecular diagnosis. [ABSTRACT FROM AUTHOR]