Expansion of the spectrum of ITGB6-related disorders to adolescent alopecia, dentogingival abnormalities and intellectual disability

Eur J Hum Genet. 2016 Aug;24(8):1223-7. doi: 10.1038/ejhg.2015.260. Epub 2015 Dec 23.

Abstract

Alopecia with mental retardation (APMR) is a very rare disorder. In this study, we report on a consanguineous Pakistani family (AP91) with mild-to-moderate intellectual disability, adolescent alopecia and dentogingival abnormalities. Using homozygosity mapping, linkage analysis and exome sequencing, we identified a novel rare missense variant c.898G>A (p.(Glu300Lys)) in ITGB6, which co-segregates with the phenotype within the family and is predicted to be deleterious. Structural modeling shows that Glu300 lies in the β-propeller domain, and is surrounded by several residues that are important for heterodimerization with α integrin. Previous studies showed that ITGB6 variants can cause amelogenesis imperfecta in humans, but patients from family AP91 who are homozygous for the c.898G>A variant present with neurological and dermatological features, indicating a role for ITGB6 beyond enamel formation. Our study demonstrates that a rare deleterious variant within ITGB6 causes not only dentogingival anomalies but also intellectual disability and alopecia.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Alopecia / diagnosis
  • Alopecia / genetics*
  • Child
  • Female
  • Humans
  • Integrin beta Chains / chemistry
  • Integrin beta Chains / genetics*
  • Intellectual Disability / diagnosis
  • Intellectual Disability / genetics*
  • Male
  • Mutation, Missense
  • Pedigree
  • Phenotype*
  • Protein Domains
  • Syndrome
  • Tooth Abnormalities / diagnosis
  • Tooth Abnormalities / genetics*

Substances

  • Integrin beta Chains
  • integrin beta6