Niemann-Pick Disease with the Type A phenotype is based on a severe deficiency in acid sphingomyelinase, which results in accumulation of sphingomyelin and other lipids within lysosomes of monocytes and macrophages.


Inheritance: autosomal recessive, parents may be of Ashkenazic Jewish descent


Clinical features:

(1) normal pregnancy and delivery

(2) variable prolonged jaundice at birth

(3) onset of illness during infancy with failure to thrive

(4) hepatosplenomegaly, resulting in a protuberant abdomen

(5) moderate lymphadenopathy

(6) recurrent vomiting

(7) difficulty feeding

(8) malnutrition

(9) chronic constipation

(10) eye examination may show a macula that is cherry red or a gray granular appearing

(11) variable problems with aspiration pneumonia

(12) chest X-rays show a diffuse reticular or finely nodular pulmonary infiltrate without change in respiratory function

(13) progressive muscle hypotonia and weakness

(14) absent or markedly diminished deep tendon reflexes

(15) progressive deterioration in mental function

(16) skin color brownish-yellow or ochre colored

(17) osteoporosis


Laboratory findings

(1) acid sphingmyelinase activity < 5%

(2) lipid-laden foam cells (Niemann-Pick Disease or NPD cells) in bone marrow or liver biopsy


Course: death occurs in early childhood (2 to 3 or 4 to 5 years of age, depending on source)


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