A Simple Composite Phenotype Scoring System for Evaluating Mouse Models of Cerebellar Ataxia

We describe a protocol for the rapid and sensitive quantification of disease severity in mouse models of cerebellar ataxia. Measures include hind limb clasping, ledge test, gait and kyphosis. This protocol effectively discriminates between affected and non-affected individuals, and detects the progression of affected individuals over time.

We describe a protocol for the rapid and sensitive quantification of disease severity in mouse models of cerebella ataxia. It is derived from previously published phenotype assessments in several disease models, including spinocerebellar ataxias, Huntington s disease and spinobulbar muscular atrophy. Measures include hind limb clasping, ledge test, gait and kyphosis. Each measure is recorded on a scale of 0-3, with a combined total of 0-12 for all four measures. The results effectively discriminate between affected and non-affected individuals, while also quantifying the temporal progression of neurodegenerative disease phenotypes. Measures may be analyzed individually or combined into a composite phenotype score for greater statistical power. The ideal combination of the four described measures will depend upon the disorder in question. We present an example of the protocol used to assess disease severity in a transgenic mouse model of spinocerebellar ataxia type 7 (SCA7).

Albert R. La Spada and Gwenn A. Garden contributed to this manuscript equally.

To prevent bias, the experimenter performing the assessments should not have knowledge of the animal's genotype. Individual measures are scored on a scale of 0-3, with 0 representing an absence of the relevant phenotype and 3 representing the most severe manifestation. Each test is performed multiple times to ensure that the score is reproducible. Obesity will complicate the interpretation of all measures described. The investigator may wish to weigh mice following phenotype scoring to assess the possible role of adiposity in the results.

Ledge test

The ledge test is a direct measure of coordination, which is im....

This protocol is designed to be a sensitive and easily performed evaluation of disease severity in mouse models of cerebellar ataxia. Individual components of the scoring system will be more or less effective in different mouse models of neurodegeneration.

Elements of this scoring system have been effectively used to assess a variety of mouse models of human neurodegenerative disease, including cerebellar ataxias, Huntington s disease and spinobulbar muscular atrophy [1-3]. The ideal combinat.......

These studies were approved by the University of Washington Institutional Animal Care and Use Committee.

This work was supported by NIH grants NS052535 to G.A.G and EY014061 & EY014997 to A.R.L., as well as a UL1DE019583-02 consortium award.