Niemann–Pick disease

Niemann-Pick Disease 2

Niemann–Pick disease is a group of inherited metabolic disorders in which harmful quantities of lipids accumulate in the spleen, liver, lungs, bone marrow, and brain. These disorders are caused by genetic mutations that affect the body's ability to metabolize lipids properly.

Classification

Niemann–Pick disease is classified into several types based on the specific genetic mutations and the resulting enzyme deficiencies:

• Type A and Type B are caused by mutations in the SMPD1 gene, leading to a deficiency in the enzyme acid sphingomyelinase.
• Type C is caused by mutations in the NPC1 or NPC2 genes, which affect the transport of cholesterol and other lipids within cells.

Symptoms

The symptoms of Niemann–Pick disease vary depending on the type and severity of the disorder. Common symptoms include:

• Enlarged spleen and liver (hepatosplenomegaly)
• Difficulty with motor skills
• Ataxia
• Dysarthria
• Dysphagia
• Seizures
• Progressive neurological decline

Diagnosis

Diagnosis of Niemann–Pick disease typically involves a combination of clinical evaluation, family history, and specialized tests such as:

• Genetic testing to identify mutations in the SMPD1, NPC1, or NPC2 genes
• Enzyme assay to measure acid sphingomyelinase activity
• Cholesterol esterification test for Type C

Treatment

There is currently no cure for Niemann–Pick disease, and treatment focuses on managing symptoms and improving quality of life. Treatment options may include:

• Enzyme replacement therapy for Type B
• Miglustat for Type C
• Supportive therapies such as physical therapy, occupational therapy, and speech therapy

Prognosis

The prognosis for individuals with Niemann–Pick disease varies depending on the type and severity of the disorder. Type A is typically fatal in early childhood, while individuals with Type B may live into adulthood with proper management. Type C has a highly variable prognosis, with some individuals living into adulthood.

Related Pages

• Lysosomal storage disease
• Genetic disorder
• Metabolic disorder
• Sphingolipidosis
• Cholesterol metabolism