Homozygous MED25 mutation implicated in eye-intellectual disability syndrome

Hum Genet. 2015 Jun;134(6):577-87. doi: 10.1007/s00439-015-1541-x. Epub 2015 Mar 20.

Abstract

Genetic syndromes involving both brain and eye abnormalities are numerous and include syndromes such as Warburg micro syndrome, Kaufman oculocerebrofacial syndrome, Cerebro-oculo-facio-skeletal syndrome, Kahrizi syndrome and others. Using exome sequencing, we have been able to identify homozygous mutation p.(Tyr39Cys) in MED25 as the cause of a syndrome characterized by eye, brain, cardiac and palatal abnormalities as well as growth retardation, microcephaly and severe intellectual disability in seven patients from four unrelated families, all originating from the same village. The protein encoded by MED25 belongs to Mediator complex or MED complex, which is an evolutionary conserved multi-subunit RNA polymerase II transcriptional regulator complex. The MED25 point mutation is located in the von Willebrand factor type A (MED25 VWA) domain which is responsible for MED25 recruitment into the Mediator complex; co-immunoprecipitation experiment demonstrated that this mutation dramatically impairs MED25 interaction with the Mediator complex in mammalian cells.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Abnormalities, Multiple / metabolism
  • Abnormalities, Multiple / pathology
  • Adolescent
  • Animals
  • Cell Line
  • Child
  • Child, Preschool
  • Eye Abnormalities / genetics*
  • Eye Abnormalities / metabolism
  • Eye Abnormalities / pathology
  • Female
  • Homozygote*
  • Humans
  • Infant
  • Infant, Newborn
  • Intellectual Disability / genetics*
  • Intellectual Disability / metabolism
  • Intellectual Disability / pathology
  • Male
  • Mediator Complex / genetics*
  • Mediator Complex / metabolism
  • Protein Structure, Tertiary
  • RNA Polymerase II / genetics
  • RNA Polymerase II / metabolism
  • Syndrome

Substances

  • MED25 protein, human
  • Mediator Complex
  • RNA Polymerase II