A truncating mutation of TRAPPC9 is associated with autosomal-recessive intellectual disability and postnatal microcephaly

Am J Hum Genet. 2009 Dec;85(6):897-902. doi: 10.1016/j.ajhg.2009.10.027.


Although autosomal genes are increasingly recognized as important causes of intellectual disability, very few of them are known. We identified a genetic locus for autosomal-recessive nonsyndromic intellectual disability associated with variable postnatal microcephaly through homozygosity mapping of a consanguineous Israeli Arab family. Sequence analysis of genes in the candidate interval identified a nonsense nucleotide change in the gene that encodes TRAPPC9 (trafficking protein particle complex 9, also known as NIBP), which has been implicated in NF-kappaB activation and possibly in intracellular protein trafficking. TRAPPC9 is highly expressed in the postmitotic neurons of the cerebral cortex, and MRI analysis of affected patients shows defects in axonal connectivity. This suggests essential roles of TRAPPC9 in human brain development, possibly through its effect on NF-kappaB activation and protein trafficking in the postmitotic neurons of the cerebral cortex.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism
  • Carrier Proteins / genetics*
  • Carrier Proteins / physiology*
  • Chromosome Mapping
  • Consanguinity
  • Gene Expression Regulation, Developmental
  • Genes, Recessive
  • Homozygote
  • Humans
  • Intellectual Disability / genetics*
  • Intercellular Signaling Peptides and Proteins
  • Magnetic Resonance Imaging / methods
  • Mice
  • Microcephaly / genetics*
  • Mitosis
  • Mutation*
  • NF-kappa B / genetics
  • Neurons / metabolism


  • Carrier Proteins
  • Intercellular Signaling Peptides and Proteins
  • NF-kappa B
  • TRAPPC9 protein, human