Novel Mutation in Chromosome 11p15.4 Causing Niemann-Pick Disease Type A in a Saudi Child.

Niemann-Pick disease (NPD) encompasses a minimum of three lysosomal storage diseases, all of which are inherited in an autosomal recessive manner. Acid sphingomyelinase (ASM) deficiency is the cause of NPD types A and B. ASM is the enzyme that hydrolyzes the sphingolipid sphingomyelin. An 18-month-old patient with progressive painless abdominal distension with organomegaly and neurological deficits presented to our hospital. Brain imaging and laboratory findings did not show anything, but there was a millstone growth delay. The diagnosis of NPD type A was confirmed by a genetic examination, which revealed a twofold change on chromosome 11p15.4 in the region encoding the sphingomyelin phosphodiesterase-1 (SMPD1) gene. The patient was followed up with no specific treatment, and signs of respiratory infections were later reported.