Identification of genomic deletions spanning the PCDH19 gene in two unrelated girls with intellectual disability and seizures

Clin Genet. 2012 Dec;82(6):540-5. doi: 10.1111/j.1399-0004.2011.01812.x. Epub 2011 Dec 13.

Abstract

Recently, missense and truncating mutations in the gene PCDH19 have been reported to cause female-restricted epilepsy with mental retardation (EFMR). EFMR (MIM#300088) is an X-linked disorder characterized by early onset seizures and intellectual disability (ID). Interestingly, unlike typical X-linked mode of inheritance, the phenotype is restricted to females, and males are unaffected carriers. PCDH19 is highly expressed in brain, and the encoded protein belongs to the cadherin superfamily. Here we report two unrelated female patients with deletions spanning PCDH19 identified by copy number variation (CNV) analysis and validated by qPCR. In one, we have identified a 3 Mb interstitial deletion at Xq21.33-q22.1 which spans PCDH19, LOC442459 & TNMD. This patient had her first seizure at 8 months old, and also has ID and aggressive behavior. In another female patient we identified a de novo 603 kb heterozygous deletion in a female patient with fits (since 1 year of age), ID, hyperactivity and aggressive behavior. The deletion spans the entire PCDH19 gene (also TNMD, SRPX2, TSPAN6 and SYTL4). In conclusion, our results suggest that deletions at PCDH19 also cause EFMR.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Cadherins / genetics*
  • DNA Copy Number Variations
  • Female
  • Genetic Diseases, X-Linked / genetics*
  • Humans
  • Intellectual Disability / genetics*
  • Microarray Analysis
  • Protocadherins
  • Real-Time Polymerase Chain Reaction
  • Seizures / genetics*
  • Sequence Deletion / genetics*
  • X Chromosome Inactivation / genetics

Substances

  • Cadherins
  • PCDH19 protein, human
  • Protocadherins