Recessively inherited amyotrophic lateral sclerosis: a Germany family with the D90A CuZn-SOD mutation

The epidemiology of CuZn-SOD mutations in Germany: a study of 217 families

We screened 217 patients from Germany (n = 213), Austria (n = 2) and Switzerland (n = 2) with a positive family history for amyotrophic lateral sclerosis (ALS) for mutations in the copper/zinc superoxide dismutase (SOD1) gene. We found that 13% of the families tested carried mutations. By analyzing inheritance, we detected a clear-cut co-segregation in 5 of the 28 families; however, in two families with an established mutation, co-segregation was absent. In Germany, the R115G mutation is comparatively frequent and exhibits a specific aggressive phenotype. The L144F mutation, which is the most prevalent mutation in the Balkan countries, and the D90A mutation which is the most frequent SOD1 mutation globally, seem to be the second most common disease-causing mutations in Germany.

CuZn-Superoxide Dismutase in D90A Heterozygotes from Recessive and Dominant ALS Pedigrees

Mutations in CuZn-superoxide dismutase (CuZn-SOD) have been linked to ALS. In most cases ALS is inherited as a dominant trait and there is marked reduction in CuZn-SOD activity in samples from the patients. The D90A mutation, however, mostly causes ALS as a recessive trait and shows near normal CuZn-SOD activity. A few familial and sporadic ALS cases heterozygous for the D90A mutation have also been found. Haplotype analysis of both types of D90A families has suggested that all recessive cases share a common founder and may carry a protective factor located close to the D90A mutant CuZn-SOD locus. To search for effects of a putative protective factor we analysed erythrocytes from D90A heterozygous individuals for SOD activity by a direct assay, subunit composition by immunoblotting, and zymogram pattern formed by isoelectric focusing and SOD staining. Included were heterozygotes from 17 recessive families, and from 2 dominant families and 4 apparently sporadic cases. The CuZn-SOD activity in the recessive and dominant groups was found to be equal, and 95% of controls. The ratio between mutant and wildtype subunits was likewise equal and 0.8:1 in both groups. The zymograms revealed multiple bands representing homo- and heterodimers. There were, however, no differences between the groups in patterns or in ratios between the molecular forms. In conclusion we find no evidence from analyses in erythrocytes that the putative protective factor in recessive families acts by simply downregulating the synthesis or altering the molecular structure or turnover of the mutant enzyme.

Progress in the modeling of neurodegenerative diseases in transgenic mice

Transgenic mouse models exist for the major neurodegenerative diseases, including Alzheimer's disease, tauopathy and amyotrophic lateral sclerosis. Although many of the mice do not completely replicate the human disease they are intended to model, they have provided insight into the mechanisms that underlie disease etiology. In the case of the Alzheimer's disease and amyotrophic lateral sclerosis models, the mice have also provided a therapeutic testing ground for the testing of agents that have been shown to have considerable clinical promise.