Prenatal diagnosis by FISH in a family with Pelizaeus-Merzbacher disease caused by duplication of the PLP gene

A diagnosis of Pelizaeus-Merzbacher disease (MIM 312080) was made in a youn g boy. No mutation in the coding region of the proteolipid protein (PLP) ge ne had been found. The boy's maternal aunt came for prenatal diagnosis when 16+ weeks pregnant and carrying a male fetus. Samples were tested for dupl ication of the PLP gene, by interphase FISH, in lymphocyte preparations fro m the proband, his aunt and an amniotic fluid cell preparation from the fet us. The proband was found to carry the duplication, thus confirming the dia gnosis of Pelizaeus-Merzbacher disease, but neither the aunt nor the fetus carried a duplication. Copyright (C) 1999 John Wiley & Sons, Ltd.