High-resolution array-CGH in patients with oculocutaneous albinism identifies new deletions of the TYR, OCA2, and SLC45A2 genes and a complex rearrangement of the OCA2 gene

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.