ABCA4 sequence variants in Chinese patients with age-related macular degeneration or Stargardt's disease.

ABCA4 gene sequence alterations cause Stargardt's disease (STGD) and may cause some age-related macular degeneration (AMD). We sought to shed light on these associations among Hong Kong Chinese by genotyping 140 AMD, 18 STGD and 95 normal control subjects for 15 ABCA4 exons which were reported to often contain AMD- or STGD-associated mutations. Sequence alterations R212H, T1428M, V1433I, T1572M, I2166M, IVS6-5T>G and IVS33+1G>T were found in AMD patients. T1428M and R2040X occurred in STGD patients. Control subjects displayed all the above missense alterations but no splicing or nonsense changes. Therefore, ABCA4 splicing mutations may be associated with a small proportion of AMD cases.