De novo variant in KIF26B is associated with pontocerebellar hypoplasia with infantile spinal muscular atrophy

Am J Med Genet A. 2018 Dec;176(12):2623-2629. doi: 10.1002/ajmg.a.40493. Epub 2018 Aug 27.

Abstract

KIF26B is a member of the kinesin superfamily with evolutionarily conserved functions in controlling aspects of embryogenesis, including the development of the nervous system, though its function is incompletely understood. We describe an infant with progressive microcephaly, pontocerebellar hypoplasia, and arthrogryposis secondary to the involvement of anterior horn cells and ventral (motor) nerves. We performed whole exome sequencing on the trio and identified a de novo KIF26B missense variant, p.Gly546Ser, in the proband. This variant alters a highly conserved amino acid residue that is part of the phosphate-binding loop motif and motor-like domain and is deemed pathogenic by several in silico methods. Functional analysis of the variant protein in cultured cells revealed a reduction in the KIF26B protein's ability to promote cell adhesion, a defect that potentially contributes to its pathogenicity. Overall, KIF26B may play a critical role in the brain development and, when mutated, cause pontocerebellar hypoplasia with arthrogryposis.

Keywords: KIF26B; arthrogryposis; kinesin; microcephaly; pontocerebellar hypoplasia.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Brain / abnormalities
  • Brain / diagnostic imaging
  • Cell Adhesion
  • Disease Models, Animal
  • Gene Expression
  • Humans
  • Kinesin / chemistry
  • Kinesin / genetics*
  • Magnetic Resonance Imaging / methods
  • Mice
  • Models, Molecular
  • Olivopontocerebellar Atrophies / genetics*
  • Protein Conformation
  • Spinal Muscular Atrophies of Childhood / diagnosis*
  • Spinal Muscular Atrophies of Childhood / genetics*
  • Whole Exome Sequencing

Substances

  • KIF26B protein, human
  • Kinesin

Supplementary concepts

  • Pontocerebellar Hypoplasia Type 1