Novel variants associated with Stargardt disease in Chinese patients

Abstract

Purpose: Stargardt disease (STGD) is the most frequent cause of hereditary macular dystrophy in childhood. Variants in the ABCA4, ELOVL4, PROM1, BEST1, and PRPH2 genes have been detected in patients with autosomal recessive or dominant STGD. This study was aimed at identifying the novel disease-associated variants in Chinese patients with STGD.

Methods: Ten Chinese families and two sporadic cases with STGD (n = 32) were enrolled in the study. All subjects underwent genetic analysis with next-generation sequencing (NGS), which was based on a specially customized capture panel targeting exons and untranslated regions (UTRs) of 792 genes related to common hereditary ophthalmopathy. Variants were analyzed to assess possible pathogenicity.

Results: Fourteen disease-associated variants of ABCA4 were detected in 9 Chinese families with autosomal recessive STGD, including 11 pathogenic variants and 3 likely pathogenic variants. Variant c.4253 + 4C > T in ABCA4 was identified as one de novo variant. Of the 14 distinct variants in ABCA4, 7 novel variants were found. In addition, one known variant of PROM1, c.1117C > T (p.Arg373Cys), was detected in one family and one sporadic case with autosomal dominant STGD, respectively. One novel missense variant of ELOVL4, c.59A > G (p.Asn20Ser), was found in one sporadic case with autosomal dominant STGD. The potential deleterious effects of these novel variants were confirmed through intensive analysis.

Conclusion: By panel-based NGS, 8 novel disease-associated variants are identified in two genes responsible for STGD, including ABCA4 and ELOVL4. Our results further extend the mutation spectrum of these two genes in Chinese patients with STGD. One ABCA4 c.4253 + 4C > T variant is identified as a de novo splicing variant.

Keywords: Chinese patients; Next-generation sequencing; Novel pathogenic variants; STGD.