Preimplantation genetic diagnosis for Niemann-Pick disease type B.

Background: Acid sphingomyelinase (ASM) deficient Niemann-Pick disease (NPD) is an autosomal recessive disorder caused by mutations in the ASM gene (SMPD1). More than 70 different mutations have been reported in this gene. NPD type B is the most common type in Saudi Arabia with a frequency of 1:40 000 to 1:100 000.