Evaluation of the ELOVL4, PRPH2 and ABCA4 genes in patients with Stargardt macular degeneration.

Mutations in the ATP-binding cassette, subfamily A, member 4 (ABCA4), elongation of very long chain fatty acids 4 (ELOVL4) and peripherin-2 (PRPH2) genes have been identified in patients with Stargardt macular degeneration (STGD). The aim of this study was to investigate which of these genes is responsible for susceptibility in Chinese patients. A total of 41 probands with STGD or suspected STGD were enrolled in the study. The coding regions and adjacent intronic sequences of the ELOVL4 and PRPH2 genes and 3 coding exons of the ABCA4 gene were amplified by polymerase chain reaction (PCR). The nucleotide sequences of the amplicons were determined by Sanger sequencing. Three novel heterozygous missense mutations in the ABCA4 gene were identified: c:2633C>A (p:Ser878X), c:5646G>A (p:Met1882Ile) and c:6389T>A (p:Met2130Lys). These mutations were not present in 176 normal individuals and were predicted to be pathogenic. Two benign variations were found: a reported variation, c:5682G>C in ABCA4 and a novel variation, c:699G>A in ELOVL4. In addition, 5 single nucleotide polymorphisms (SNPs: rs3812153, rs7764439, rs390659, rs434102 and c:929G>A) were detected in ELOVL4 and PRPH2. The c:929G>A variation has not been previously reported. We conclude that no pathogenic variations in ELOVL4 and PRPH2 were detected in the Chinese STGD patients. Our results imply that ABCA4 is more likely to be significant in Chinese STGD patients.