Homozygous microdeletion in the 11p13 region in the patient with isolated form of aniridia: New challenges in the genetic diagnostics of aniridia

<jats:title>Abstract</jats:title><jats:p>Aniridia is usually an autosomal dominant, rare disorder characterized by a variable degree of hypoplasia or the absence of iris tissue, with additional ocular abnormalities. Pathogenic variants in the <jats:italic>PAX6</jats:italic> gene are associated with aniridia in most patients. However, in up to 30% of individuals, disease results from 11p13 chromosomal rearrangements. Here we present a patient with a clinical diagnosis of partial aniridia born to consanguineous Polish parents. The parents were asymptomatic and ophthalmologically normal. We performed <jats:italic>PAX6</jats:italic> sequencing, array comparative genomic hybridization, quantitative real‐time PCR, and whole genome sequencing. aCGH revealed a homozygous deletion of the <jats:italic>DCDC1</jats:italic> gene fragment in the patient. The same, but heterozygous deletion, was detected in each of the patient's asymptomatic parents and brother. In the presented family, the signs and symptoms of aniridia are observed only in the homozygous proband. Whole genome sequencing analysis was performed to determine other possible causes of the disease and did not detect any additional or alternative potentially pathogenic variant. We report a novel homozygous deletion located in the 11p13 region, which does not include the <jats:italic>PAX6</jats:italic> gene or any known <jats:italic>PAX6</jats:italic> enhancers. To our best knowledge, this is the first reported case of a patient presented with isolated aniridia carrying a homozygous microdeletion downstream of the <jats:italic>PAX6</jats:italic> gene.</jats:p>