Niemann-Pick disease

Niemann-Pick disease (NPD) is actually a collection of a number of distinct autosomal recessive lysosomal storage diseases. They are divided into two groups of two based on the underlying metabolic deficiency:

• deficiency of acid sphingomyelinase ^1,3,4
  • Niemann-Pick disease type A (NPD-A)
    • severe hepatosplenomegaly in infancy
    • severe central nervous system involvement, with atrophy or white matter T2 signal increase on MRI ¹
    • usually, succumb to the disease by 2 years of age ^1,3,4
  • Niemann-Pick disease type B (NPD-B)
    • hepatosplenomegaly
    • minimal CNS involvement ⁴
    • variable age of onset and more indolent clinical course ^1​​
• impaired intracellular cholesterol trafficking ¹ 
  • Niemann-Pick disease type C (NPD-C)
    • pronounced CNS involvement with atrophy or white matter T2 signal increase on MRI ¹
    • mild hepatosplenomegaly
  • Niemann-Pick disease type D (NPD-D)
    • Nova Scotian ancestry ¹