Genetic analysis of contiguous X-chromosome deletion syndrome encompassing the BTK and TIMM8A genes

J Hum Genet. 2011 Aug;56(8):577-82. doi: 10.1038/jhg.2011.61. Epub 2011 Jul 14.

Abstract

Patients with X-linked agammaglobulinemia (XLA) can present with sensorineural deafness. This can result from a gross deletion that not only involved the Bruton's tyrosine kinase (BTK) gene, but also TIMM8A, mutations in which underlie the Mohr-Tranebjærg syndrome (MTS). We analyzed the genomic break points observed in three XLA-MTS patients and compared these with deletions break points from XLA patients. Patient 1 had a 63-kb deletion with break points in intron 15 of BTK and 4 kb upstream of TAF7L. Patients 2 and 3 had 149.7 and 196 kb deletions comprising BTK, TIMM8A, TAF7L and DRP2. The break points in patients 1 and 3 were located in Alu and endogenous retrovirus (ERV) repeats, whereas the break points in patient 2 did not show involvement of transposable elements. Comparison of gross deletion sizes and involvement of transposable elements in XLA and XLA-MTS patients from the literature showed preferential involvement of Alu elements in smaller deletions (<10 kb). These results show further insights into the molecular mechanisms underlying gross deletions in patients with primary immunodeficiency.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Agammaglobulinaemia Tyrosine Kinase
  • Agammaglobulinemia / genetics
  • Alu Elements / genetics
  • Child
  • Chromosome Breakpoints
  • Chromosome Deletion*
  • Chromosomes, Human, X / genetics*
  • Deaf-Blind Disorders / genetics
  • Dystonia / genetics
  • Gene Deletion
  • Genetic Diseases, X-Linked / genetics
  • Humans
  • Infant
  • Intellectual Disability / genetics
  • Male
  • Membrane Transport Proteins / genetics*
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Optic Atrophy / genetics
  • Protein-Tyrosine Kinases / genetics*
  • Syndrome
  • Terminal Repeat Sequences / genetics

Substances

  • Membrane Transport Proteins
  • Mitochondrial Precursor Protein Import Complex Proteins
  • TIMM8A protein, human
  • Protein-Tyrosine Kinases
  • Agammaglobulinaemia Tyrosine Kinase
  • BTK protein, human

Supplementary concepts

  • Mohr-Tranebjaerg syndrome