Type A and B Niemann-Pick are due to deficiency of lysosomal sphingomyelinase. The involved gene is on chromosome 11p15.1-15.4. Type C (the most common subtype) is due to defective transport of cholesterol between cells and has been linked to a defect in NPC-1 gene on chromosome 18. In brain, defective cholesterol transport leads to progressive neurologic damage.
Tweets by WebPathology