| 1. |
- Ikonen, E, et al.
(författare)
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Aspartylglucosaminuria : cDNA encoding human aspartylglucosaminidase and the missense mutation causing the disease
- 1991
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Ingår i: EMBO Journal. - 0261-4189 .- 1460-2075. ; 10:1, s. 51-58
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Tidskriftsartikel (refereegranskat)abstract
- We have isolated a 2.1 kb cDNA which encodes human aspartylglucosaminidase (AGA, E.C. 3.5.1.26). The activity of this lysosomal enzyme is deficient in aspartylglucosaminuria (AGU), a recessively inherited lysosomal accumulation disease resulting in severe mental retardation. The polypeptide chain deduced from the AGA cDNA consists of 346 amino acids, has two potential N-glycosylation sites and 11 cysteine residues. Transient expression of this cDNA in COS-1 cells resulted in increased expression of immunoprecipitable AGA protein. Direct sequencing of amplified AGA cDNA from an AGU patient revealed a G----C transition resulting in the substitution of cysteine 163 with serine. This mutation was subsequently found in all the 20 analyzed Finnish AGU patients, in the heterozygous form in all 53 carriers and in none of 67 control individuals, suggesting that it represents the major AGU causing mutation enriched in this isolated population. Since the mutation produces a change in the predicted flexibility of the AGA polypeptide chain and removes an intramolecular S-S bridge, it most probably explains the deficient enzyme activity found in cells and tissues of AGU patients.
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| 2. |
- Syvänen, Ann-Christine, et al.
(författare)
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Convenient and quantitative determination of the frequency of a mutant allele using solid-phase minisequencing : application to aspartylglucosaminuria in Finland
- 1992
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Ingår i: Genomics. - 0888-7543 .- 1089-8646. ; 12:3, s. 590-595
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Tidskriftsartikel (refereegranskat)abstract
- Aspartylglucosaminuria (AGU) is a recessively inherited lysosomal disease caused by inadequate aspartylglucosaminidase (AGA) activity. The disease is prevalent in the genetically isolated Finnish population. We have used a new method, solid-phase minisequencing, to determine the frequency of two missense mutations in the AGA gene in this population. In samples from 70% of the Finnish AGU families, we found that the two nucleotide changes were always associated, and they were identified in 98% of the AGU alleles analyzed. Thus, the high prevalence of AGU in the Finnish population is the consequence of a founder effect of one ancient mutation. The identification of asymptomatic carriers by the minisequencing test proved to be unequivocal. The method also allowed quantification of a mutated nucleotide sequence present in less than 1% of a sample. The frequency of AGU carriers in this population was 1/36 when estimated by quantifying the mutated AGU allele in a pooled leukocyte sample from 1350 normal Finnish individuals.
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