α-Galactosidase A Deficiency (Full Gene Sequencing)

Blood, amniotic fluid, or CVS

7 mL whole blood, 10 mL amniotic fluid, or 10 mg CVS

Lavender-top (EDTA) tube or yellow-top (ACD) tube; sterile plastic conical tube; or two confluent T25 flasks for fetal testing

Indications for testing: Patients with clinical features of Fabry disease, both male and female; carrier testing for females with affected male relatives; patients with left ventricular hypertrophy or cardiomyopathy who otherwise do not have a classic Fabry disease phenotype; parents, siblings, and possibly children of a patient known to carry a mutation in GLA gene; prenatal testing when a parent is diagnosed with Fabry disease and has an identified GLA mutation.

This method does not detect large deletions, large duplications and genomic rearrangements, or deep intronic variants; it may be affected by allele-dropout.

DNA sequencing

Fabry disease (Anderson-Fabry disease, α-galactosidase A deficiency) is a rare, panethnic, X-linked recessive lysosomal storage disorder (LSD) characterized by a deficiency in acid α-galactosidase A caused by mutations in the GLA gene. Deficiency of this enzyme leads to accumulation of glycogen within the lysosomes and cytoplasm resulting in tissue damage. Fabry disease is rare and occurs in an estimated 1 in 100,000 newborns. Since the disorder is an X-linked recessive disease, the mother has a 50% chance of passing the defective gene on to all offspring. Males who inherit the defective gene will have Fabry disease. Females who inherit the gene will be carriers. Because of X-chromosomal inactivation, some female carriers develop symptoms of mild, moderate, or classical Fabry disease. To date, more than 300 mutations and sequence variants have been identified, the majority being very rare.