Prenatal diagnosis of duplication by single nucleotide polymorphism array in a family with Pelizaeus-Merzbacher disease.

A family with a history of Pelizaeus-Merzbacher disease (PMD) received prenatal diagnosis of gene duplication in a fetus using a single nucleotide polymorphism (SNP) array. A 27-year-old pregnant woman was referred for genetic counseling due to her four-year-old son being diagnosed with a suspected classic type of PMD. Amniocentesis was performed at 18 and 3/7 weeks of gestation, and the SNP array was carried out on DNA from the mother, her affected son, and fetus, then further confirmed by multiplex ligation-dependent probe amplification (MLPA). Cytogenetic analysis of the fetus showed 46,XY. SNP array analysis revealed that the male fetus did not carry gene duplication but the affected boy did, and the mother was a carrier for the duplication of the gene. All SNP array results were further confirmed by MLPA. SNP array and MLPA analyses of peripheral blood verified the nonduplication of the gene in the infant after birth. At present, the child (without duplication) is developing normally. This study preliminarily suggests that SNP array is a sensitive and accurate technology for identifying duplication and is feasible for reliable diagnosis, including for the prenatal diagnosis of PMD resulting from duplication.