Abstract: Objective To report the results of mutation analysis of the ABCA4 gene in a cohort of patients with Stargardt disease (STGDI) and describe their associated phenotype. Design Retrospective case series. Participants 119 suspected STGDI probands including 17 patients with family history and 102 sporadic cases were recruited. Methods All the exons including intron-exon boundary of the ABCA4 gene, were amplified by PCR and the products were analyzed by direct sequencing in all the patients. The clinical features of STGDI patients were recorded. Main Outcome Measures Mutations of ABCA4 gene, family history, fundus photography, optical coherence tomography (OCT), fundus autofluorescence (AF), electroretinogram (ERG) and visual acuity. Results 119 ABCA4 pathogenic mutations were found in 110 patients (110/119, 92.4%). Of the 136 intragenic mutations, 16 were detected for the first time in this study. The mutations contained 55.1% (75/136) of missense mutations, 15.4% (21/136) of deletions or insertions, 17.6% (24/136) of splice site mutations, and 11.8% (16/136) of nonsense mutations. The most frequent mutation in this cohort was c.2424C>G p.Y808X, identified 17 times (7.1%). The median age of onset was 12.85±9.01 years and the median BCVA upon review was 0.11±0.12. Conclusion The mutations found in this study broaden the spectrum of ABCA4 gene mutations, and Chinese patients appeared to have early onset age and severe visual defects. The mutation spectrum of the ABCA4 gene in Chinese patients is quite different from that for other populations. (Ophthalmol CHN, 2016, 25: 219-224)

Key words: Stargardt disease, ABCA4 gene