Identification of Four Novel PCDH19 Mutations and Prediction of Their Functional Impact

Emanuela Leonardi, Stefano Sartori, Marilena Vecchi, Elisa Bettella, Roberta Polli, Luca De Palma, Clementina Boniver, Alessandra Murgia

Research output: Contribution to journalArticle

Abstract

The PCDH19 gene encodes protocadherin-19, a transmembrane protein with six cadherin (EC) domains, containing adhesive interfaces likely to be involved in neuronal connection. Over a hundred mostly private mutations have been identified in girls with epilepsy, with or without intellectual disability (ID). Furthermore, transmitting hemizygous males are devoid of seizures or ID, making it difficult to establish the pathogenic nature of newly identified variants. Here, we describe an integrated approach to evaluate the pathogenicity of four novel PCDH19 mutations. Segregation analysis has been complemented with an in silico analysis of mutation effects at the protein level. Using sequence information, we compared different computational prediction methods. We used homology modeling to build structural models of two PCDH19 EC-domains, and compared wild-type and mutant models to identify differences in residue interactions or biochemical properties of the model surfaces. Our analysis suggests different molecular effects of the novel mutations in exerting their pathogenic role. Two of them interfere with or alter functional residues predicted to mediate ligand or protein binding, one alters the EC-domain folding stability; the frame-shift mutation produces a truncated protein lacking the intracellular domain. Interestingly, the girl carrying the putative loss of function mutation presents the most severe phenotype.

Original languageEnglish
Pages (from-to)389-398
Number of pages10
JournalAnnals of Human Genetics
Volume78
Issue number6
DOIs
Publication statusPublished - Nov 1 2014

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Keywords

  • EFMR
  • Epilepsy
  • in silico analysis
  • Pathogenicity
  • PCDH19

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics
  • Medicine(all)

Cite this

Leonardi, E., Sartori, S., Vecchi, M., Bettella, E., Polli, R., De Palma, L., Boniver, C., & Murgia, A. (2014). Identification of Four Novel PCDH19 Mutations and Prediction of Their Functional Impact. Annals of Human Genetics, 78(6), 389-398. https://doi.org/10.1111/ahg.12082