A new gene involved in X-linked mental retardation identified by analysis of an X;2 balanced translocation

Nat Genet. 2000 Feb;24(2):167-70. doi: 10.1038/72829.


X-linked forms of mental retardation (MR) affect approximately 1 in 600 males and are likely to be highly heterogeneous. They can be categorized into syndromic (MRXS) and nonspecific (MRX) forms. In MRX forms, affected patients have no distinctive clinical or biochemical features. At least five MRX genes have been identified by positional cloning, but each accounts for only 0.5%-1.0% of MRX cases. Here we show that the gene TM4SF2 at Xp11.4 is inactivated by the X breakpoint of an X;2 balanced translocation in a patient with MR. Further investigation led to identification of TM4SF2 mutations in 2 of 33 other MRX families. RNA in situ hybridization showed that TM4SF2 is highly expressed in the central nervous system, including the cerebral cortex and hippocampus. TM4SF2 encodes a member of the tetraspanin family of proteins, which are known to contribute in molecular complexes including beta-1 integrins. We speculate that through this interaction, TM4SF2 might have a role in the control of neurite outgrowth.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Brain / metabolism*
  • Cerebral Cortex / metabolism
  • Child
  • Chromosome Mapping
  • Chromosomes, Human, Pair 2*
  • Exons
  • Female
  • Hippocampus / metabolism
  • Humans
  • Intellectual Disability / genetics*
  • Karyotyping
  • Male
  • Membrane Proteins
  • Molecular Sequence Data
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / genetics*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Tetraspanins
  • Translocation, Genetic*
  • X Chromosome*


  • Membrane Proteins
  • Nerve Tissue Proteins
  • TSPAN7 protein, human
  • Tetraspanins

Associated data

  • GENBANK/AJ250562
  • GENBANK/AJ250563
  • GENBANK/AJ250564
  • GENBANK/AJ250565
  • GENBANK/AJ250566
  • GENBANK/AJ250567
  • GENBANK/AJ250568
  • GENBANK/AJ250569
  • GENBANK/AJ250570
  • GENBANK/AJ250571
  • GENBANK/AJ250572
  • GENBANK/AJ250573
  • GENBANK/AJ250574
  • GENBANK/AJ250575
  • GENBANK/AJ250576
  • GENBANK/AJ250577
  • GENBANK/AJ250578
  • GENBANK/AJ250579
  • GENBANK/D26483
  • GENBANK/D29808
  • GENBANK/U49081