ABCA4 variant screening in a Turkish cohort with Stargardt disease

ABSTRACT

Purpose

This study aims to evaluate the ABCA4 variants in patients diagnosed with Stargardt disease.

Methods

This is a retrospective study designed to investigate variants in the ABCA4 in Stargardt disease and the clinical findings of the cases. Sex, age, age of onset of symptoms, best-corrected visual acuity, color fundus photography, optical coherence tomography, and visual field test of the patients were recorded. Genetic analyses were screened, and patients with at least two variants in the ABCA4 were included in this study.

Results

Twenty-seven patients diagnosed with Stargardt disease with the ABCA4 variants were included in this study. Twelve of them (44.4%) were female and fifteen (55.5%) were male. The mean age of the cases was 27.44 years (ranging from 8 to 56 years). Thirty different variants were detected in 54 ABCA4 alleles of 27 patients. The two most common pathogenic variants were c.5882 G>A p.(Gly1961Glu) and c.52C>T p.(Arg18Trp) in this cohort. Two novel variants were identified (c.3855_3856dup, c.1554 + 3_1554 + 4del) and the patient with the c.1554 + 3_1554 + 4del variant additionally had a different ABCA4 variant in trans. The other novel variant was homozygous.

Conclusions

In this study, two novel variants were described in a Turkish cohort with Stargardt disease. The variant c.52C>T p.(Arg18Trp) was the most common disease-causing variant besides the c.5882 G>A p.(Gly1961Glu) which was identified frequently in the previous studies. A larger sample size is necessary for describing different pathogenic variants and understanding the phenotype-genotype correlations.

KEY MESSAGES

Identifying variants and their pathogenicity in inherited diseases is important for widening the disease-causing mutations and future treatment options.

Two novel variants (c.3855_3856dup, c.5910_5912dup) were described in a cohort with Stargardt disease.

The most common variants could be different in ethnic groups.

The variant c.52C>T p.(Arg18Trp) was the most common variant besides the c.5882G>A p.(Gly1961Glu) which was frequently identified in the previous studies.

Describing different pathogenic variants and clinical findings of the patients is important for understanding the phenotype-genotype correlations.

KEYWORDS:

• Stargardt disease
• ABCA4
• next-generation sequencing
• retinal degeneration

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.