|
|
|||
Description:Krabbe disease is an autosomal recessive neurodegenrative disorder caused by the deficiency of the enzyme galactocerebrosidase (GALC). It is characterized by demyelination of the central and peripheral nervous systems and accumulation of globoid cells in brain white matter. Krabbe disease occurs in approximately one in 100,000 births in the United States. The carrier frequency in individuals with no family history is about one in 150. Approximately 90% of the patients have the early-infantile form while the remaining 10% have late-onset Krabbe disease. A 30 kb deletion starting within the large intron 10 and continuing beyond the end of the gene accounts for 40-50% of the mutant alleles in individuals of European ancestry. Sequence analysis of the entire GALC gene, which also detects the common 30 kb deletion, is available on a clinical basis at the Medical Genetics Laboratories at Baylor College of Medicine . Reasons for Referral:
Testing Methodology:PCR amplification of the exons contained in the GALC gene coding region and the junction fragment from the common 30 kb deletion will be performed on patient genomic DNA. Direct sequencing of amplification products is performed in both the forward and reverse directions using automated fluorescence dideoxy sequencing methods. Specimen Requirements:Blood: EDTA (purple-top) tubes: Adult: 14 cc; Child: 6 cc; Infant: 2-3 cc Turnaround Time:Index: 4 weeks CPT Codes and Prices:Index: 83891, 83898x20, 83894, 83904x40, 83909x40,
83912 Shipping InformationForms:>> Gene Sequencing Requisition References:Rafi MA, Luzi P, Chen YQ, Wenger DA. (1995). A large deletion together with a point mutation in the GALC gene is a common mutant allele in patients with infantile Krabbe disease. Human Molecular Genetics 4: 12851289. Test Codes:Index: 6415 |