Treatment of Oculocutaneous/Ocular Albinism and for Increasing Pigmentation

Description:

Abstract:

Albinism (also called achromia, achromasia, or achromatosis) is a congenital disorder characterized by the complete or partial absence of pigment in the skin, hair and eyes due to absence or defect in any one of a number of proteins involved in the production of melanin. Certain forms of albinism are known to be due to mutations in tyrosine metabolism. In oculocutaneous albinism (OCA), pigment is lacking in the eyes, skin and hair. In ocular albinism, only the eyes lack pigment. Patients with albinism experience varying degrees of vision loss associated with foveal hypoplasia, nystagmus, photophobia and/or glare sensitivity, refractive errors, and abnormal decussation of ganglion cell axons at the optic chiasm. Current treatment options for vision problems caused by albinism are limited to correction of refractive errors and amblyopia, low vision aids, and (in some cases) extraocular muscle surgery.

Nitisinone (NTBC) is an FDA-approved drug used in the treatment of tyrosinemia, type 1. The drug blocks the normal degradation pathway of tyrosine thus allowing greater circulating plasma levels of tyrosine. NEI investigators identified administration of NTBC to subjects (e.g., mice or humans) with certain forms of albinism, can result in increased circulating tyrosine levels, an increase in tyrosinase activity, and, subsequently, increased pigmentation. Co-development research agreements with companies are sought to advance this treatment to humans.