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Spectrum of mutations in alpha-mannosidosis
T Berg1, H M Riise, G M Hansen
1Department of Medical Genetics, University Hospital and University of Tromso, N-9037, Norway.
American Journal of Human Genetics
|January 23, 1999
Summary
This study identified 21 new mutations causing alpha-mannosidosis, a rare genetic disorder. A common mutation (R750W) was found in 21% of European patients, highlighting genetic diversity in alpha-mannosidosis.
Area of Science:
- Biochemistry
- Genetics
- Rare Diseases
Background:
- Alpha-mannosidosis is an autosomal recessive lysosomal storage disorder.
- It results from alpha-mannosidase deficiency, leading to oligosaccharide accumulation and severe symptoms.
- Previous research identified the first mutation in Palestinian siblings.
Purpose of the Study:
- To identify novel mutations causing alpha-mannosidosis in patients of mainly European descent.
- To analyze the spectrum of genetic alterations and their frequency.
- To investigate genotype-phenotype correlations.
Main Methods:
- Screening of 43 patients from 39 families for mutations.
- Identification of mutations through sequencing and analysis of polymorphic sites.
- Southern blot analysis for detecting rearrangements.
- Enzyme activity assays in fibroblast cultures.
Main Results:
- 21 novel mutations and 4 polymorphic positions were identified.
- Disease-causing mutations were found in 72% of alleles, including splicing, missense, nonsense, insertions, and deletions.
- A recurrent missense mutation (R750W) accounted for 21% of disease alleles in European patients.
- No significant LAMAN activity was detected in any fibroblast cultures.
- No clear correlation between mutation type and clinical manifestations was observed.
Conclusions:
- The study expands the known mutation spectrum for alpha-mannosidosis.
- Genetic heterogeneity exists, but a recurrent mutation is prevalent in European populations.
- Further research is needed to understand genotype-phenotype relationships in alpha-mannosidosis.