Eight previously unidentified mutations found in the <it>OA1 </it>ocular albinism gene

• Main Authors: Dufier Jean-Louis, Kaplan Josseline, Mezer Eedy, Said Edith, Lacombe Didier, Sutherland Joanne, Levin Alex V, Héon Elise, Bonneau Dominique, Munier Francis L, Schorderet Daniel F, Dollfus Hélène, Marchant Dominique, Jaliffa Carolina, Vêtu Christelle, Roche Olivier, Mayeur Hélène, Marsac Cécile, Menasche Maurice, Abitbol Marc
• Format: Article
• Language: English
• Published: BMC 2006-04-01
• Series: BMC Medical Genetics
• Online Access: http://www.biomedcentral.com/1471-2350/7/41

<p>Abstract</p> <p>Background</p> <p>Ocular albinism type 1 (OA1) is an X-linked ocular disorder characterized by a severe reduction in visual acuity, nystagmus, hypopigmentation of the retinal pigmented epithelium, foveal hypoplasia, macromelanosomes in pigmented skin and eye cells, and misrouting of the optical tracts. This disease is primarily caused by mutations in the <it>OA1 </it>gene.</p> <p>Methods</p> <p>The ophthalmologic phenotype of the patients and their family members was characterized. We screened for mutations in the <it>OA1 </it>gene by direct sequencing of the nine PCR-amplified exons, and for genomic deletions by PCR-amplification of large DNA fragments.</p> <p>Results</p> <p>We sequenced the nine exons of the <it>OA1 </it>gene in 72 individuals and found ten different mutations in seven unrelated families and three sporadic cases. The ten mutations include an amino acid substitution and a premature stop codon previously reported by our team, and eight previously unidentified mutations: three amino acid substitutions, a duplication, a deletion, an insertion and two splice-site mutations. The use of a novel Taq polymerase enabled us to amplify large genomic fragments covering the <it>OA1 </it>gene. and to detect very likely six distinct large deletions. Furthermore, we were able to confirm that there was no deletion in twenty one patients where no mutation had been found.</p> <p>Conclusion</p> <p>The identified mutations affect highly conserved amino acids, cause frameshifts or alternative splicing, thus affecting folding of the OA1 G protein coupled receptor, interactions of OA1 with its G protein and/or binding with its ligand.</p>