Technical advances in prenatal diagnosis of tyrosinase-negative oculocutaneous albinism.

Technical advances in the prenatal diagnosis of tyrosinase-negative oculocutaneous albinism, the most severe subtype of this disease, are reviewed. Ultrastructural examination of hair bulb melanocytes in fetal skin during the second trimester of pregnancy was the first successful method for the prenatal diagnosis of oculocutaneous albinism. Subsequent introduction of the electron microscopic DOPA reaction test in fetal skin provided safer, more practical, and reliable information for diagnosing tyrosinase-negative oculocutaneous albinism prenatally. The recent elucidation of the specific gene mutation of tyrosinase in the affected individuals now allows the DNA-based prenatal diagnosis of tyrosinase-negative oculocutaneous albinism in the first trimester of pregnancy.