Brown oculocutaneous albinism. Clinical, ophthalmological, and biochemical characterization.
The clinical, ophthalmological, and biochemical characteristics of a 28-year-old black woman with brown oculocutaneous albinism were determined. Hair color was medium brown and skin color was light brown, and a faint tan developed with sun exposure. The irides were light brown in the central one-third, blue-gray in the peripheral two-thirds, and showed punctate and radial translucency. Visual acuity was 20/60 in the right eye and 20/100 in the left eye. There was a moderate pendular nystagmus, and previous surgeries had corrected an exotropia. The foveal reflex was muted, and the retinal pigment was reduced. Hairbulb tyrosinase activity was 1.75 pmoles/120 min/hairbulb, hairbulb glutathione content 0.83 nmoles/hairbulb, and urine excretion of 5-S-cysteinyldopa 174.9 ng/mg creatinine. Electron microscopy of hairbulb and skin melanocytes showed arrested melanosomal development. These findings suggest that there is a partial block in the distal eumelanin pathway in this form of albinism. The ophthalmological characteristics of six additional cases of this form of albinism are also presented.
D000328:Adult; D000417:Albinism / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D044383:Black People; D003548:Cysteinyldopa / Q000378:metabolism; D005123:Eye / Q000503:physiopathology*; D005260:Female; D005654:Fundus Oculi; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008854:Microscopy, Electron; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010375:Pedigree; D012867:Skin / Q000648:ultrastructure
D003548:Cysteinyldopa; D014442:Monophenol Monooxygenase; D005978:Glutathione