High‐resolution array‐<scp>CGH</scp> in patients with oculocutaneous albinism identifies new deletions of the <i><scp>TYR</scp>,<scp> OCA</scp>2</i>, and <i><scp>SLC</scp>45A2</i> genes and a complex rearrangement of the <i><scp>OCA</scp>2</i> gene

Abstract

Oculocutaneous albinism (OCA) is caused by mutations in six different genes, and their molecular diagnosis encompasses the search for point mutations and intragenic rearrangements. Here, we used high-resolution array-comparative genome hybridization (CGH) to search for rearrangements across exons, introns and regulatory sequences of four OCA genes: TYR, OCA2, TYRP1, and SLC45A2. We identified a total of ten new deletions in TYR, OCA2, and SLC45A2. A complex rearrangement of OCA2 was found in two unrelated patients. Whole-genome sequencing showed deletion of a 184-kb fragment (identical to a deletion previously found in Polish patients), whereby a large portion of the deleted sequence was re-inserted after severe reshuffling into intron 1 of OCA2. The high-resolution array-CGH presented here is a powerful tool to detect gene rearrangements. Finally, we review all known deletions of the OCA1-4 genes reported so far in the literature and show that deletions or duplications account for 5.6% of all mutations identified in the OCA1-4 genes.