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Paediatric Laboratory Medicine

Gaucher Disease: GBA Recurrent Mutations

Clinical Significance

Gaucher disease (GD) is the most common lipid-storage disorder, with variable symptoms ranging from no outward symptoms to severe disability. The most common symptoms of Gaucher disease are enlargement of the liver and spleen, anemia, reduced platelets (resulting in easy bruising and long clotting times), bone pain and osteoporosis. There are three clinical forms of Gaucher disease, which are distinguished by the occurrence and form of neurological involvement. Type 1 GD does not have any neurological symptoms. Type 2 GD is characterized by severe neurological symptoms, and is usually fatal during the first three years of life. Type 3 GD also shows neurological symptoms, but they appear later in childhood and progress more slowly than the symptoms of Type 2 GD.

Gaucher disease is an autosomal recessive disorder caused by mutations in the acid b-glucosidase (GBA) gene, located on chromosome 1 (1p21 p23). Although GD has been reported in individuals of various ethnic backgrounds, it occurs most often in people of Ashkenazi Jewish ancestry. Over 100 different mutations in this gene have been identified in affected patients; however four mutations in the GBA gene account for over 90% of the mutations seen in Ashkenazi Jewish individuals affected with Gaucher disease [84G>GG, IVS2(+1)G>A, N370S and L444P]. These four mutations account for 50-60% of disease-causing alleles seen in the non-Jewish population. Non-Jewish individuals with Gaucher disease tend to be compound heterozygotes with one common mutation and one 'rare' mutation of which four are tested for in this panel [D55bp, V394L, D409H and R496H].

To be affected with GD, an individual must have two mutations in the GBA gene (one inherited from each parent); these may or may not be identical mutations. Any person with one copy of the defective GBA gene is a Gaucher disease carrier. Carriers do not have, and will not develop, Gaucher disease. However, if two carriers wish to have children, there is a one in four chance (25%) that their baby will be born with the disease. There is a three in four chance (75%) that their baby will not have Gaucher disease.

An accurate biochemical test is available for the diagnosis of Gaucher disease consisting of the analysis of b-glucosidase activity in plasma, leucocytes or cultured cells. This test should be considered before molecular analysis is undertaken. Molecular identification of the mutation in individuals with a confirmed diagnosis can be used for carrier testing and prenatal diagnosis in the family. The biochemical test is not reliable for identifying carriers.

Test Name

Gaucher Disease: GBA Recurrent Mutations

Alternate Name/ Synonym

  • Glucocerebrosidase deficiency
  • Glucosylceramide deficiency

Gene Name

  • GBA

Test Code

GAUCH

Division

Molecular Genetics

Method

Targeted analysis of recurrent mutations

External Proficiency Testing

CAP

Turn Around Time

2 weeks (Prenatal samples), 2-3 weeks (Pregnancy/Urgent samples), 4-6 weeks (Routine)

Protein

Glucosylceramidase; glucosidase, beta, acid

Disease/Condition

Gaucher Disease

Specimen Type

Blood; gDNA. 

For details about specimen requirements, please refer to: Specimen Type & Requirement (PDF).

Minimum Specimen Requirements

5-10 mL EDTA or ACD 0.5 mL EDTA (neonate); minimum 10 ug in 100 uL low TE (pH8.0)

Storage/Transportation

Room Temperature

Special Requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Approval is not required

CPT Codes

81251

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Interpretation

Interpretation is provided in report

Information Sheet: Gaucher Disease