With the mapping of the locus CHM for choroideremia and the subsequent cloning of the gene, reliable carrier and prenatal diagnosis has become a possibility. We discuss our experience with prenatal diagnosis of choroideremia, an X-linked choroidoretinal dystrophy leading to blindness in otherwise healthy males. In the period 1987-1995, five prenatal diagnoses have been performed by either indirect linkage analysis or by detection of the disease-causing mutation, reflecting the impact of molecular biology in clinical genetic practice.