Know Your Disease: Niemann-Pick disease type ‘A’ Disease
What is Niemann-Pick disease type ‘A’?
Niemann-Pick disease is one of the lysosomal storage disorders that affects the metabolism of sphingolipids.
What are the symptoms of Niemann-Pick disease type ‘A’?
· progressive loss of mental abilities and movement
· Interstitial lung disease that can cause recurrent lung infections and eventually lead to respiratory failure.
Children with Niemann-Pick disease type A generally do not survive past early childhood.
How common is the disease?
Niemann-Pick disease type A occurs more frequently among individuals of Ashkenazi (eastern and central European) Jewish descent than in the general
population. The incidence within the Ashkenazi population is approximately 1 in 40,000 individuals.
What genes are related to Niemann-Pick disease type ‘A’ disease?
SMPD1 gene provides instructions for producing an enzyme called acid sphingomyelinase. Acid sphingomyelinase is responsible for the conversion of a fat
(lipid) called sphingomyelin into another type of lipid called ceramide. Mutations in SMPD1 lead to a shortage of acid sphingomyelinase, which results in
reduced break down of sphingomyelin, causing this fat to accumulate in cells. This fat buildup causes cells to malfunction and eventually die.
How do people inherit Niemann-Pick disease type ‘A’ disease?
This condition is inherited in an autosomal recessive pattern.
How is Niemann-Pick disease type ‘A’ disease diagnosed?
NPC type ‘A’ disease is diagnosed based on thorough clinical evaluation, identification of characteristic symptoms, detailed patient history. Acid
sphingomyelinase enzyme activity can be measured in leucocytes or skin fibroblasts. Diagnosis can be confirmed by molecular genetic testing detecting
mutations in the SMPD1 gene.
Prenatal diagnosis can be performed through chorionic villus biopsy or amniocentesis, if the mutations in the family are known.