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Paediatric Laboratory Medicine

Fabry Disease: GLA mRNA Analysis

Clinical Significance

Fabry disease results from the build-up of fatty substances in the walls of blood vessels, particularly the small vessels in the skin, kidneys, heart, and nervous system. The channels of these vessels become narrowed, leading to decreased blood flow. Symptoms associated with Fabry disease include an inability to sweat, fever attacks, atrophy of the cornea, and purple skin lesions called angiokeratomas. As the disease progresses, kidney, heart and neurological complications may develop.

The fatty substances, called glycosphingolipids, accumulate because patients are unable to produce a-galactosidase A, an enzyme needed to break down these fats. The enzyme is lacking due to mutations in the a-galactosidase A (GLA) gene on the X chromosome (Xq22.1). Males normally have one X chromosome in each cell. If that X chromosome carries the mutation in the GLA gene, the boy will have Fabry disease. Females normally have two X chromosomes in each cell. If one X chromosome carries the mutation in the GLA gene and the other one does not, the girl will be a carrier of Fabry disease. In rare cases, a female carrier will show some symptoms of the disease (manifesting carrier), although most carriers do not have and will not develop Fabry disease. Carrier females may, however, pass the mutation on to their children. If a female is a carrier, her sons have a 50 per cent chance of inheriting the mutation and being affected with Fabry disease. Her daughters are unlikely to be affected by Fabry disease but have a 50 per cent chance of inheriting the mutation and being carriers themselves.

An accurate biochemical test is available for the diagnosis of Fabry disease consisting of the analysis of a-galactosidase A 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

Fabry Disease: GLA mRNA Analysis

Alternate Name/ Synonym

  • GLA deficiency
  • Alpha-Galactosidase A deficiency
  • Anderson-Fabry disease
  • Angiokeratoma Corporis Diffusum
  • Ceramide Trihexosidase deficiency
  • Hereditary dystopic lipidosis

Gene Name

  • GLA

Alternate Gene Name

GALA

Test Code

FABRY

Division

Molecular Genetics

Method

mRNA analysis

External Proficiency Testing

CAP

Turn Around Time

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

Protein

Alpha-galactodidase

Disease/Condition

Fabry Disease

Specimen Type

Blood; gDNA.

For details about specimen requirements, please refer to: Specimen Type & Requirements (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

81405

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: Fabry Disease