¹Human Medical Genetics Program, University of Colorado Denver, Anshutz Medical Campus, Aurora, Colorado, USA

Correspondence: Professor Richard A. Spritz, University of Colorado Denver, Anschutz Medical Campus, Human Medical Genetics Program, P.O. Box 6511, MS 8300, Aurora, CO 80045, USA. E-mail: richard.spritz@uchsc.edu

Received 1 October 2007; Revised 31 January 2008; Accepted 15 March 2008; Published online 8 May 2008.

Abstract

Oculocutaneous albinism (OCA) is a genetically heterogeneous group of disorders characterized by absent or reduced pigmentation of the skin, hair, and eyes. In humans, four genes have been associated with "classical" OCA and another 12 genes with syndromic forms of OCA. To assess the prevalence of different forms of OCA and different gene mutations among non-Hispanic Caucasian patients, we performed DNA sequence analysis of the four genes associated with "classical" OCA (TYR, OCA2, TYRP1, SLC45A2), the two principal genes associated with syndromic OCA (HPS1, HPS4), and a candidate OCA gene (SILV), in 121 unrelated, unselected non-Hispanic/Latino Caucasian patients carrying the clinical diagnosis of OCA. We identified apparent pathologic TYR gene mutations in 69% of patients, OCA2 mutations in 18% , SLC45A2 mutations in 6% , and no apparent pathological mutations in 7% of patients. We found no mutations of TYRP1, HPS1, HPS4, or SILV in any patients. Although we observed a diversity of mutations for each gene, a relatively small number of different mutant alleles account for a majority of the total. This study demonstrates that, contrary to long-held clinical lore, OCA1, not OCA2, is by far the most frequent cause of OCA among Caucasian patients.