SSCP analysis by RT-PCR for the prenatal diagnosis of Niemann-Pick disease type C.
The molecular prenatal diagnosis of Niemann-Pick disease type C (NPC) is presented. The proband with a late infantile type of NPC was a compound heterozygote of a paternal missense mutation, T529G, and a maternal 2 bp deletion at nt 350 of the NPC1 gene. These mutations were detected by single-strand conformation polymorphism (SSCP) analysis of RT-PCR products. When the proband was aged 4 years 3 months, prenatal diagnosis for the second child was performed using both biochemical and molecular methods. SSCP analysis for the parental mutations using cDNA from cultured amniotic fluid cells revealed the absence of both mutations and the fetus was diagnosed as being unaffected. This diagnosis was supported by a normal level of cholesterol esterification using cultured amniotic fluid cells. After the child's birth, when he was 21 months old, the diagnosis was confirmed by SSCP analysis of genomic DNAs of his family. This analysis also revealed a unique variation of intron 13, IVS13+753-758 del TTTTTT, that was shared only by the proband and the father, and was suspected as being linked to the T529G missense mutation. A combination of both biochemical and molecular analyses is very useful and reliable for prenatal diagnosis of Niemann-Pick disease type C.