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
PIGMENT CELL & MELANOMA RESEARCH
Authors: Morice-Picard, Fanny; Lasseaux, Eulalie; Cailley, Dorothee; Gros, Audrey; Toutain, Jerome; Plaisant, Claudio; Simon, Delphine; Francois, Stephane; Gilbert-Dussardier, Brigitte; Kaplan, Josseline; Rooryck, Caroline; Lacombe, Didier; Arveiler, Benoit
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.
Interactions Between HERC2, OCA2 and MC1R May Influence Human Pigmentation Phenotype
ANNALS OF HUMAN GENETICS
Authors: Branicki, Wojciech; Brudnik, Urszula; Wojas-Pelc, Anna
Abstract
Human pigmentation is a polygenic trait which may be shaped by different kinds of gene-gene interactions. Recent studies have revealed that interactive effects between HERC2 and OCA2 may be responsible for blue eye colour determination in humans. Here we performed a population association study, examining important polymorphisms within the HERC2 and OCA2 genes. Furthermore, pooling these results with genotyping data for MC1R, ASIP and SLC45A2 obtained for the same population sample we also analysed potential genetic interactions affecting variation in eye, hair and skin colour. Our results confirmed the association of HERC2 rs12913832 with eye colour and showed that this SNP is also significantly associated with skin and hair colouration. It is also concluded that OCA2 rs1800407 is independently associated with eye colour. Finally, using various approaches we were able to show that there is an interaction between MC1R and HERC2 in determination of skin and hair colour in the studied population sample.