Description
The D91A variant in the SOD1 gene has been reported multiple times, using alternate nomenclature (D90A), in association with familial ALS. When found in the homozygous and compound heterozygous state D91A has been reported as a disease-associated variant (Hand et al., 2001; Andersen et al., 1995; Felbecker et al., 2010). However, in the heterozygous state the pathogenicity of the the D91A variant is debated (Al-Chalabi et al., 1998; Felbecker et al., 2010). The D91A variant is found with significant frequency among Scandinavian populations (Al-Chalabi et al., 1998); and the NHLBI ESP Exome Sequencing Project reports D91A was observed at a frequency of 0.08%, 7/8600 alleles, from individuals of European ancestry, indicating it may be a rare variant in this population. The D91A variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is not conserved across species. Functional studies suggest that the D91A variant may not alter protein activity and stability to the same degree as other established SOD1 variants associated with familial ALS (Själander et al., 1995; Fujisawa et al., 2012; Lindberg et al., 2002). Given the available information, we interpret D91A as a variant of unknown significance.
| # | Sample | Method | Observation |
|---|
| Origin | Affected | Number tested | Tissue | Purpose | Method | Individuals | Allele frequency | Families | Co-occurrences |
|---|
| 1 | germline | yes | not provided | not provided | not provided | | not provided | not provided | not provided | not provided |
