Acid sphingomyelinase-deficient niemann-pick disease

The first case of Niemann-Pick disease (NPD) was described in 1914 by the German pediatrician, Albert Niemann (Niemann, 1914). Over the ensuing years, numerous reports of infants with similar clinical manifestations appeared, and in 1927 Ludwig Pick distinguished this disorder from infantile Gaucher disease based on the differential appearance of the bone marrow foam cells (Pick, 1927). The first adults with this disease were described in 1946 (Pflander, 1946; Dusendschon, 1946). By 1925, NPD was known as a storage disease, and the storage material was thought to consist primarily of phospholipid and cholesterol (Bloom, 1925; Sobotka, Epstein, and Lichtenstein, 1930). Later Klenk (1934) identified the phospholipid as sphingomyelin. A deficiency of acid sphingomyelinase (ASM; EC 3.1.4.12) activity was first demonstrated in human tissue samples obtained from NPD patients in 1966 In 1961, Crocker classified NPD into four clinical entities, types A to D (Crocker, 1961). The infantile, neurodegenerative phenotype originally described by Niemann was termed type A. Type B NPD was distinguished from this severe neuronopathic phenotype by the absence of primary neurological involvement, later onset of hepatosplenomegaly, and survival into adulthood. Types C and D, initially thought to be allelic forms of types A and B (based on similar morphological and clinical findings), are now known to be distinct disorders (Pentchev et al., 1984; Carstea et al., 1997). This chapter discusses only types A and B NPD, which are also referred to as ASM-deficient NPD.