A look into…Niemann-Pick
October is Niemann-Pick awareness month! Not sure what Niemann-Pick is? Then read on…
Niemann-Pick disease (NP) groups a series of extremely rare lysosomal storage disorders; only 91 people were diagnosed with Niemann-Pick in the UK in 2010. It is characterized by the accumulation of sphingomyelin; a lipid found in cell membranes. There are 3 types: A, B and C.
Types A and B are caused by a mutation of the SMPD1 gene causing a deficiency in the enzyme responsible for the breakdown of sphingomyelin, acid sphingomyelinase (ASM). In type A, a patient’s ASM activity is less than 1% of that of non-sufferers. Type C patients, unlike A and B, have a mutated NPC1 or NPC2 gene, and ASM deficiency is a secondary effect of lipid accumulation. All three are autosomal-recessive, meaning if both parents are carriers there is a 25% chance that their child will have NP. Although higher incidence has been reported in certain populations, all types are pan-ethnic. NP onset can occur at any age, however in type A it is usually infantile with few surviving past their 3rd birthday. Types B and C are usually diagnosed in childhood and adolescence respectively; later onset tends to correlate with a better prognosis.
There are many co-morbid conditions between the three types, ranging from neurodegenerative to cardiopulmonary. We have formulated over 120 sub-populations of this orphan disease.
Did you know... Hepatomegaly, one of the major symptoms of type B which presents itself in over 70% of cases is only present in 11% of type C patients?