Niemann-Pick disease
Alternate Names : Sphingomyelinase deficiency
Symptoms & Signs
Type A usually begins in the first few months of life. Symptoms may include: - Abdominal (belly area) swelling within 3 - 6 months
- Cherry red spot in the eye
- Feeding difficulties
- Loss of early motor skills (gets worse over time)
Type B symptoms are usually milder and occur in late childhood or adolescence. Abdominal swelling may be seen in early childhood, but there is almost no neurological involvement, such as loss of motor skills. Some patients may have repeated respiratory infections.
Type C usually affects school-aged children, but the disease may occur any time between early infancy to adulthood. Symptoms may include: - Difficulty in posturing of limbs (dystonia)
- Enlarged spleen
- Enlarged liver
- Jaundice at (or shortly after) birth
- Learning difficulties and progressive intellectual decline (dementia)
- Seizures
- Slurred, irregular speech
- Sudden loss of muscle tone which may lead to falls (cataplexy)
- Tremors
- Trouble moving the eyes up and down (vertical supranuclear gaze palsy)
- Unsteady gait, clumsiness, walking problems (ataxia)
Symptoms of Type D are similar to Type C. Type E occurs in adults. Symptoms include swelling of the spleen and neurological problems. Little is known about this rare type of Niemann-Pick disease. Symptoms and disease progression of all forms of Niemann-Pick vary from person to person. No single symptom should be used to include or exclude Niemann-Pick as a diagnosis. Other, more common, diseases may cause symptoms similar to Niemann-Pick. A person in the early stages of the disease may show only a few symptoms. Not every symptom will be seen in the later stages of the disease.
Diagnosis & Tests
Type A and B are diagnosed by measuring the amount of ASM in white blood cells. The test can be done using a blood or bone marrow sample. Such testing can tell who has the disease, but does not reveal who may be carriers. DNA tests can be done to diagnose carriers of Type A and B. A skin biopsy is usually used to diagnose Type C and Type D Niemann-Pick. Laboratory scientists will watch how the skin cells grow and study how they move and store cholesterol. DNA tests may also be done to look for the two genes that cause Niemann-Pick disease Type C. Additional tests might include: - Slit-lamp eye exam
- Liver biopsy or bone marrow aspiration
- Liver biopsy (usually not necessary)
- Sphingomyelinase assays
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