Prenatal diagnosis of adrenoleukodystrophy (ALD) was performed by means of genetic and biochemical analysis using chorionic villi and amniocytes. The mother was a carrier of an exonic point mutation in the ALD protein gene (2154 C to T) which resulted in the premature formation of a termination codon (Q590STOP) and deletes the Pst I site. Two patients in this family were hemizygotes for this mutation. Pst I digestion of cDNA from chorionic villi revealed that the fetus was a heterozygote for this mutation, and sex determination using the polymerase chain reaction (PCR) indicated female. Lignocerate oxidation in cultured amniocytes was slightly decreased. These findings suggest that the fetus is a female carrier of ALD, and the resultant baby was female.