ELECTRON MICROSCOPY OF MELANOCYTES IN HUMAN PIEBALDISM

[摘要] Melanocytes of hypopigmented epidermis from the general body surface of a piebald human subject showed a much greater tendency than normal to be dissociated from flanking keratinocytes, and the cytoplasm of many exhibited a characteristically empty appearance. In addition to non-melanized premelanosomes of normal structure, premelanosomes and melanosomes of frankly abnormal morphology were present in these cells. Melanocytes of the apparently normal pigmented epidermis revealed similar features but to a much lesser degree. In the white forelock region of the scalp, the basal epidermal melanocytes were replaced by Langerhans cells, a situation identical with that found in vitillgo, and one which strongly reinforces the suggestion that the 2 cell types are related. The above findings show that the melanocytes in piebaldism are more profoundly affected than in oculo-cutaneous (total) albinism, a situation which light microscopy has failed to reveal. The plurality of defects in piebaldism involving such features as melanocyte morphology and the basic protein structure of the melanosome indicates that a number of different gene loci are concerned in determining this condition.