A lysosomal storage disease due to sphingomyelin accumulation in the reticuloendothelial system; there are five types distinguished by age of onset, amount of central nervous system involvement, and degree of enzyme deficiency. At least some types are characterized by foamy reticular cells containing phospholipids which infiltrate the liver, spleen, lungs, lymph nodes, and bone marrow.Niemann-Pick disease types A and B occur when cells in the body do not have an enzyme called acid sphingomyelinase (ASM). Type A occurs in all races and ethnicities. It is more common in the Ashkenazi (Eastern European) Jewish population. Type C occurs when the body cannot properly break down cholesterol and other fats (lipids). This leads to too much cholesterol in the liver and spleen and too much of other lipids in the brain. Type C is most common among Puerto Ricans of Spanish descent. Type D involves a defect that interferes with how cholesterol moves between brain cells. It is a variant of type C.
It causes Abdominal (belly area) swelling within 3 to 6 months, Seizures, Unsteady gait, clumsiness, walking problems, Difficulty moving limbs, Jaundice at birth. Some forms of the disease can be diagnosed during ante natal screening. After birth, the diagnosis is made by a liver biopsy where liver tissue specimens are obtained and studied under a microscope. Niemann-Pick disease does not have a complete cure, though treatments that halt the disease progression are being studied. Affected children tend to die of infection or progressive dysfunction of the central nervous system.The official statistic is that Niemann-Pick Type C strikes an estimated 1 in 150,000 people. Currently, there are approximately 500 known cases worldwide, and just over 100 in the United States. However, the number is thought to be at least 1500 or more worldwide, because the disease is so hard to diagnose, and so often gets MIS-diagnosed.There is current research aiming to develop recombinant human acid sphingomyelinase for the potential treatment of NP disease types A and B. A phase 1 clinical trial was completed in 2009. A phase 2 trial is planned.