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Genetics Lab

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GM1 Gangliosidosis Enzyme Assay

The GM1 gangliosidoses are caused by a deficiency of beta-galactosidase, with resulting abnormal storage of acidic lipid materials. GM1 has three forms: early infantile, late infantile, and adult.
Early infantile GM1 presents with onset shortly after birth including seizures, hepatosplenomegaly, coarsening of facial features, skeletal irregularities, joint stiffness, muscle weakness and exaggerated startle response to sound. Cherry-red spots in the eyes are common. Patients may be deaf and blind by age 1 and often die by age 3 from cardiac complications or pneumonia.
Late infantile GM1 typically presents between ages 1 and 3 years with ataxia and seizure. Onset of adult GM1 is between ages 3 and 30 with muscle atrophy, corneal clouding in some patients, and dystonia. Angiokeratomas may develop on the lower part of the trunk of the body. Most patients have a normal size liver and spleen.

Test Name: GM1 Gangliosidosis (beta-galactosidase)
Test Code:
B GAL; LE FIB
Test Description:
Quantitative measurement of GM1 ganglioside activity in white blood cells or cultured fibroblasts.
Synonyms:
beta galactosidase; GM1 gangliosidosis
Indication:
This test is used to diagnose GM1 gangliosidosis in a symptomatic individual. This test is not appropriate for determining carrier status or for prenatal diagnosis.
Related Tests:
Clinical Links: GM1 Gangliosidosis OMIM entry
Availability:
Mon-Fri
Turnaround Time:
7-10 days
Methodology:
Fluorometric enzyme assay
Reference Range:
Interpretive report is provided.
Requisition:
Consent Form:
Sample Requirements: Type
Whole blood; 10 ml ACD (yellow) or Heparin (green)tube. Do not use gel separator tubes
Fibroblasts: 2 T-25 flasks
Skin biopsy: 2-4 mm skin punch biopsy

Processing
Do not spin! Keep blood at room temperature.

Shipping
Ship overnight at room temperature. Blood sample MUST be processed within 24 hours of collection. Transport fibroblasts/biopsy in appropriate media.
Samples Received:
Mon - Fri 8:00am - 5:00pm PST. For Thursday shipping please arrange for AM courier delivery.
Special Considerations:
If fresh skin biopsy is submitted, Fibroblast Culture (CH-SKIN) must be ordered separately. Please call to discuss.
Cost:
Please e-mail Client Services or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Client Services or call at 206-987-2617 with any billing questions82657