Molecular Diagnosis of Gaucher Disease
GBA Gene Sequence Analysis
Background:
Gaucher disease is the most common lysosomal storage disease and results from the mutations of the gene coding for glucosylceramidase. Clinically, Gaucher disease encompasses three major clinical subtypes (type 1, 2, and 3) based on the absence or presence of CNS involvement, which is useful in determining prognosis and management. Traditionally, the diagnosis of Gaucher disease relies on demonstration of deficient glucosylceramidase enzyme activity in blood leukocytes. This type of assay is unreliable for carrier testing or in differentiating between type1, type 2 and 3. Molecular testing identified many disease causal mutations in the GBA gene. Four common mutations in the GBA gene account for 90-95% of disease alleles in Jewish patients and for 60-75% of alleles in non-Jewish patients. Further molecular analysis of the GBA gene to identify rare mutations will benefit some Jewish Gaucher patients and most of the non-Jewish Gaucher patients for the second disease-allele. The sequencing analysis of coding regions of the GBA gene offered in this test will detect 99% of mutations associated with Gaucher disease.
Indications for Testing:
Confirmation of diagnosis of Gaucher disease.
Carrier detection in family members at risk for a known GBA mutation.
Testing Methods:
The GBA gene coding regions are amplified by PCR. DNA sequence analysis is performed on PCR products using automated, fluorescent dideoxy sequencing methods.
Specimen Requirements:
Blood: EDTA (purple-top) tubes: Adult/Child: 5-6 cc; Infant: 2-3 cc.
or Filter paper blood spot card.
or DNA: If the DNA quality is good (A260/A280 ratio between 1.8 and 1.9), we request at least 1 microgram of DNA regardless how much volume it is. Additionally, dilution should be >50 ng/ul.
Requisition form is required for each specimen. Please contact the laboratory for more detailed information.
Turnaround Time:
4 weeks
CPT codes and prices:
| Sample | CPT codes | Prices |
| Index case | 81479 (formerly 83891, 83898x11, 83904x11, 83909, 83912) | $2335 |
| Index case - 4-panel mutation | 81251 (formerly 83891, 83898x4, 83904x4, 83909, 83912) | $967 |
| Family member for known mutation | 81479 (formerly 83891, 83898x2, 83904x2, 83909, 83912) | $681 |
References:
Koprivica V, et al (2000). Am J Hum Genet 66:1777-86.
Meikle PJ, et al (1999). JAMA 281:249-54.
Coutre PL, et al (1997). Hum Genet 99:816-21.
Horowitz M, et al (1993). Am J Hum Genet 53:921-930.
Hruska K, et al (2008). Hum Mutat 29:567-583.
Pastores GM (September 2013). Gaucher disease. GeneReviews (www.geneclinics.org)