Identification of novel RP2 mutations in a subset of X-linked retinitis pigmentosa families and prediction of new domains

Maria Giuseppina Miano, Francesco Testa, Francesco Filippini, Mariajosè Trujillo, Ivan Conte, Carmela Lanzara, Josè Maria Millán, Carmelilia De Bernardo, Barbara Grammatico, Massimo Mangino, Isabella Torrente, Romeo Carrozzo, Francesca Simonelli, Ernesto Rinaldi, Valerio Ventruto, Michele D'Urso, Carmen Ayuso, Alfredo Ciccodicola

Research output: Contribution to journalArticle

Abstract

X-linked Retinitis Pigmentosa (XLRP) shows a huge genetic heterogeneity with almost five distinct loci on the X chromosome. So far, only two XLRP genes have been identified, RPGR (or RP3) and RP2, being mutated in approximately 70% and 10% of the XLRP patients. Clinically there is no clearly significative difference between RP3 and RP2 phenotypes. In the attempt to assess the degree of involvement of the RP2 gene, we performed a complete mutation analysis in a cohort of patients and we identified five novel mutations in five different XLRP families. These mutations include three missense mutations, a splice site mutation, and a single base insertion, which, because of frameshift, anticipates a stop codon. Four mutations fall in RP2 exon 2 and one in exon 3. Evidence that such mutations are different from the 21 RP2 mutations described thus far suggests that a high mutation rate occurs at the RP2 locus, and that most mutations arise independently, without a founder effect. Our mutation analysis confirms the percentage of RP2 mutations detected so far in populations of different ethnic origin. In addition to novel mutations, we report here that a deeper sequence analysis of the RP2 product predicts, in addition to cofactor C homology domain, further putative functional domains, and that some novel mutations identify RP2 amino acid residues which are evolutionary conserved, hence possibly crucial to the RP2 function.

Original languageEnglish
Pages (from-to)109-119
Number of pages11
JournalHuman Mutation
Volume18
Issue number2
DOIs
Publication statusPublished - 2001

Keywords

  • MAP domain
  • Mutation analysis
  • NM23 domain
  • Retinal disease
  • Retinitis pigmentosa 2, X-linked
  • RP2
  • XLRP

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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    Miano, M. G., Testa, F., Filippini, F., Trujillo, M., Conte, I., Lanzara, C., Millán, J. M., De Bernardo, C., Grammatico, B., Mangino, M., Torrente, I., Carrozzo, R., Simonelli, F., Rinaldi, E., Ventruto, V., D'Urso, M., Ayuso, C., & Ciccodicola, A. (2001). Identification of novel RP2 mutations in a subset of X-linked retinitis pigmentosa families and prediction of new domains. Human Mutation, 18(2), 109-119. https://doi.org/10.1002/humu.1160