An inactivating mutation in intestinal cell kinase, ICK, impairs hedgehog signalling and causes short rib-polydactyly syndrome

Hum Mol Genet. 2016 Sep 15;25(18):3998-4011. doi: 10.1093/hmg/ddw240. Epub 2016 Jul 27.

Abstract

The short rib polydactyly syndromes (SRPS) are a group of recessively inherited, perinatal-lethal skeletal disorders primarily characterized by short ribs, shortened long bones, varying types of polydactyly and concomitant visceral abnormalities. Mutations in several genes affecting cilia function cause SRPS, revealing a role for cilia function in skeletal development. To identify additional SRPS genes and discover novel ciliary molecules required for normal skeletogenesis, we performed exome sequencing in a cohort of patients and identified homozygosity for a missense mutation, p.E80K, in Intestinal Cell Kinase, ICK, in one SRPS family. The p.E80K mutation abolished serine/threonine kinase activity, resulting in altered ICK subcellular and ciliary localization, increased cilia length, aberrant cartilage growth plate structure, defective Hedgehog and altered ERK signalling. These data identify ICK as an SRPS-associated gene and reveal that abnormalities in signalling pathways contribute to defective skeletogenesis.

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Abnormalities, Multiple / physiopathology
  • Cilia / genetics
  • Cilia / pathology
  • Exome / genetics
  • Female
  • Hedgehog Proteins / genetics*
  • Humans
  • Infant
  • MAP Kinase Signaling System
  • Pedigree
  • Pregnancy
  • Protein Serine-Threonine Kinases / genetics*
  • Sequence Analysis, DNA
  • Short Rib-Polydactyly Syndrome / genetics*
  • Short Rib-Polydactyly Syndrome / pathology
  • Signal Transduction
  • Skeleton / abnormalities
  • Skeleton / growth & development*

Substances

  • Hedgehog Proteins
  • CILK1 protein, human
  • Protein Serine-Threonine Kinases