MAP1B mutations cause intellectual disability and extensive white matter deficit

Nat Commun. 2018 Aug 27;9(1):3456. doi: 10.1038/s41467-018-05595-6.

Abstract

Discovery of coding variants in genes that confer risk of neurodevelopmental disorders is an important step towards understanding the pathophysiology of these disorders. Whole-genome sequencing of 31,463 Icelanders uncovers a frameshift variant (E712KfsTer10) in microtubule-associated protein 1B (MAP1B) that associates with ID/low IQ in a large pedigree (genome-wide corrected P = 0.022). Additional stop-gain variants in MAP1B (E1032Ter and R1664Ter) validate the association with ID and IQ. Carriers have 24% less white matter (WM) volume (β = -2.1SD, P = 5.1 × 10-8), 47% less corpus callosum (CC) volume (β = -2.4SD, P = 5.5 × 10-10) and lower brain-wide fractional anisotropy (P = 6.7 × 10-4). In summary, we show that loss of MAP1B function affects general cognitive ability through a profound, brain-wide WM deficit with likely disordered or compromised axons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism
  • Brain / pathology
  • Cognition / physiology
  • Corpus Callosum / metabolism
  • Corpus Callosum / pathology
  • Female
  • Fragile X Mental Retardation Protein / genetics
  • Fragile X Mental Retardation Protein / metabolism*
  • Intellectual Disability / genetics
  • Intellectual Disability / physiopathology
  • Male
  • Mice
  • Mice, Knockout
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Mutation / genetics
  • Pedigree
  • White Matter / metabolism*
  • White Matter / pathology*

Substances

  • Fmr1 protein, mouse
  • Microtubule-Associated Proteins
  • microtubule-associated protein 1B
  • Fragile X Mental Retardation Protein