Discrimination of individual and concurrent glycosylation and polyadenylation mutations causing pseudo-deficiency of arylsulfatase A from mutations causing metachromatic leukodystrophy
- Wayne State Univ. School of Medicine, Detroit, MI (United States)
Pseudo-deficiency (PD) of arylsulfatase A (ASA) is a benign condition of ASA deficiency that cannot be distinguished biochemically from metachromatic leukodystrophy (MLD). Two A{r_arrow}G transitions were identified in a number of PD alleles. One abolishes an N-glycosylation site and the other modifies a polyadenylation signal. These mutations were detected simultaneously be allele-specific PCR amplification of about 1 kilobase of DNA stretching from the glycosylation site in exon 6 to the adenylation site at the 3{prime} end of the ASA gene. A pair of normal primers and a pair of mutant primers were used in this simultaneous detection procedure. This method did not work when only one of the two mutations was present. To allow detection of the individual PD mutations, we used a distinct wild-type or mutant-specific primer on one side of the amplified fragment and a common primer on the other side. Detection of individual PD mutations was also accomplished by restriction digestion. The polyadenylation mutation created a Mae III restriction site. In the case of the N-glycosylation mutation that did not produce or destroy any known restriction site, we modified a single nucleotide in one primer and were able to create a Bfa I restriction site in the mutant allele. With these methods we detected PD alleles with individual and concurrent glycosylation and adenylation mutations. While the adenylation mutation alone was rare, the glycosylation mutation alone was more common that the concurrent presence of both mutations. Detection of PD mutations in the ASA gene by allele-specific amplification and by restriction digestion should help to resolve genotypic ambiguities in diagnosis and carrier detection of MLD.
- OSTI ID:
- 134163
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0899
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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