HISTOLOGY OF FETAL EYES WITH OCULOCUTANEOUS ALBINISM

The diagnosis of tyrosinase-negative oculocutaneous albinism (OCA) was made in a 19-week-old fetus by skin biopsy. Because the parents had a n 11-year-old son with tyrosinase-negative OCA, they requested that th e fetus be aborted at the 20th week of gestation, A histological analy sis of the eyes was performed. Throughout the retina, the ganglion cel l layer was separated from the inner neuroblastic layer by the inner p lexiform layer, However, the number of ganglion cells was decreased an d the nerve fiber layer was immature. Bipolar and horizontal cells had begun to segregate into the inner nuclear layer. Rods and cones were identifiable in the posterior, but not peripheral, retina. Cones were more numerous in the center of the retina, and no rod-free area was id entifiable. In addition, the ciliary body (epithelial folds, blood ves sels in the mesodermal connective tissue core, and ciliary muscle) was less developed than in a normal fetus. Melanosomes in the retinal pig ment epithelium only contained filaments without melanization and were therefore classified as stage I or II melanosomes. However, the cilia ry epithelium also contained some stage III melanosomes with melanin a dherent to the filaments.