Fabry Disease

Alternate test name

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

Gene name / Alternate gene name

GLA
GALA

Protein

Alpha-galactosidase

Lab area

Genome Diagnostics - Molecular Genetics

Method and equipment

Deletion/duplication analysis via MLPA; mRNA Analysis; Sequencing

Expected turn-around time

Prenatal samples: 2 weeks Pregnancy/STAT: 2-3 weeks Routine: 4-6 weeks

Specimen type

Blood; extracted DNA will not be accepted for the MLPA or mRNA portions of this test.

If sending a prenatal sample, please contact the laboratory prior to sending sample to discuss sample requirements.

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

Specimen requirements

5-10 mL EDTA; minimum 0.5 mL EDTA (neonate) (Sequencing)
1 PAXgene blood RNA tube (mRNA analysis)

Storage and transportation

Blood-Room Temperature

mRNA Analysis: 1xPAXgene blood RNA tube (preferred)

Sample delivery must be within 24h of collection if contained in an EDTA tube.
Sample delivery must be within 48h of collection if contained in a PAXgene RNA tube; if <48h delivery is not possible, the sample must be stored at -80ºC until shipment.

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

DNA extracted at an external lab is not accepted for MLPA testing or mRNA analysis.

Special requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Shipping information

The Hospital for Sick Children

Division of Genome Diagnostics

555 University Avenue, Black Wing, Room 3416

Toronto, ON

Canada

M5G 1X8

Phone: 416-813-7200 ext. 2

Hours: Monday to Friday, 8 a.m. to 4:30 p.m.

Off hours: Please send to Rapid Response Laboratory, 555 University Avenue, Room 3642

Email Molecular Lab: molecular.lab@sickkids.ca

Email Cytogenetics: cytogenetics.requests@sickkids.ca

Requisition

Fabry Disease - requisition

Background and 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.

See related information sheet: Fabry Disease

Disease condition

Fabry Disease