Copyright © 2001 The American Society of Human Genetics. All rights reserved.
The American Journal of Human Genetics, Volume 69, Issue 5, 981-988, 1 November 2001
doi:10.1086/324340
Mutations in the Human Orthologue of the Mouse underwhite Gene (uw) Underlie a New Form of Oculocutaneous Albinism, OCA4
J.M. Newton1, Orit Cohen-Barak1, Nobuko Hagiwara1, John M. Gardner1, Muriel T. Davisson2, Richard A. King3 and Murray H. Brilliant1, 
, 
1 Department of Pediatrics, University of Arizona College of Medicine, Tucson
2 The Jackson Laboratory, Bar Harbor, ME
3 Department of Medicine and Institute of Human Genetics, University of Minnesota, Minneapolis
Address for correspondence and reprints: Dr. Murray H. Brilliant, Department of Pediatrics, Box 245073, University of Arizona College of Medicine, 1501 North Campbell Avenue, Tucson, AZ 85724.Abstract
Oculocutaneous albinism (OCA) affects ∼1/20,000 people worldwide. All forms of OCA exhibit generalized hypopigmentation. Reduced pigmentation during eye development results in misrouting of the optic nerves, nystagmus, alternating strabismus, and reduced visual acuity. Loss of pigmentation in the skin leads to an increased risk for skin cancer. Two common forms and one infrequent form of OCA have been described. OCA1 (MIM 203100) is associated with mutations of the TYR gene encoding tyrosinase (the rate-limiting enzyme in the production of melanin pigment) and accounts for ∼40% of OCA worldwide. OCA2 (MIM 203200), the most common form of OCA, is associated with mutations of the P gene and accounts for ∼50% of OCA worldwide. OCA3 (MIM 203290), a rare form of OCA and also known as “rufous/red albinism,” is associated with mutations in TYRP1 (encoding tyrosinase-related protein 1). Analysis of the TYR and P genes in patients with OCA suggests that other genes may be associated with OCA. We have identified the mouse underwhite gene (uw) and its human orthologue, which underlies a new form of human OCA, termed “OCA4.” The encoded protein, MATP (for “membrane-associated transporter protein”) is predicted to span the membrane 12 times and likely functions as a transporter.
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