Ophthalmologic, biochemical, platelet, and ultrastructural defects in the various types of oculocutaneous albinism

Abstract

The authors' findings indicate that the ty neg, ty pos, ym, and H P forms of albinism share the clinical features of a generalized decrease in pigmentation of the skin, hair, and eyes as well as decreased visual acuity, nystagmus, and photophobia. In general, there is an inverse relation between the amount of pigment produced in the various syndromes and the severity of the ophthalmologic defects; however, this may be modified in the ty pos, ym, and H P albino by the general ethnic pigmentary background of the patient. Ty pos albino melanocytes show dense accumulations of premelanosomes and melanosome complexes, which may indicate a defective ability to pass their products to keratinocytes. In addition to a pigment defect, the H P albinos show mild bleeding tendencies and the accumulation of lipid in bone marrow macrophages. The platelets do not undergo wave aggregation with the addition of aggregating agents, lack dense bodies, and are low in serotonin and nonmetabolic nucleotides; however, they have an intact release mechanism. The use of aspirin by this type of albino may cause him to regress from a mild bleeder to a more serious one by the blockage of the release mechanism in chemically deficient platelets. None of the various types of albinos had consistently abnormal urinary glycolipid values and no abnormal products were detected in their urine by two dimensional paper chromatography. The lipid in the bone marrow of one H P albino had the characteristics of neutral lipid and ceroid. Chromosome breaks were not found in any of the 4 types of albinism.