Variations in the ABCA4 gene are common in BEM. Two sibships showed discordant ABCA4 variants. One of these sibships illustrates that ABCA4 variants can be identified in families that have another molecular cause for their disease, due to the high prevalence of ABCA4 disease alleles in the population. The discordance evident in the second sibship may yet also be a chance finding in families with macular disease of another genetic cause, or it may represent a complex mode of inheritance determined/modified by the combination of ABCA4 alleles.

Two sibships were identified with a similar intra‐familial phenotype but discordant ABCA4 variants.

A panel of 49 subjects (comprising 40 probands/families, 7 sibling pairs and a set of three sibs) with BEM, not attributable to toxic causes, was ascertained.

To determine the frequency and nature of mutations in the gene ABCA4 in a cohort of patients with bull's‐eye maculopathy (BEM).

ABCA4 mutations and discordant ABCA4 alleles in patients and siblings with bull's‐eye maculopathy