Test Details
Methodology
DNA sequencing
Result Turnaround Time
10 - 14 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Identify which family member harbors the familial mutation and is at high risk for α-galactosidase A deficiency. 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.
Special Instructions
Once a mutation is identified in an index patient, family members can be tested for the presence of that specific mutation (single-amplicon testing). If additional amplicons are required for family testing, additional charges will apply.
Limitations
This method does not detect large deletions, large duplications and genomic rearrangements, or deep intronic variants; it may be affected by allele-dropout.
Custom Additional Information
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.
Specimen Requirements
Specimen
Blood, amniotic fluid, or CVS
Volume
7 mL whole blood, 10 mL amniotic fluid, or 10 mg CVS
Container
Lavender-top (EDTA) tube or yellow-top (ACD) tube; sterile plastic conical tube; or two confluent T25 flasks for fetal testing
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 252230 | GLA Family Targeted | 34515-7 | 252231 | GLA Family Targeted | 34515-7 | |
| Order Code | 252230 | |||||
| Order Code Name | GLA Family Targeted | |||||
| Order Loinc | 34515-7 | |||||
| Result Code | 252231 | |||||
| Result Code Name | GLA Family Targeted | |||||
| UofM | ||||||
| Result LOINC | 34515-7 |