Survival and respiratory decline are not related to homozygous SMN2 deletions in ALS patients.

The presence of the SMN2 deletion in 124 patients with ALS was investigated. Eleven patients had the homozygous deletion of SMN2 (8.8%) in comparison with 20 of 200 (10%) of the healthy control population. No significant differences in sex, age at onset, initial symptoms, form of inheritance, decline in ventilatory function, or survival time were found between patients with and without the deletion. The hypothesis that SMN2 is a prognostic factor in sporadic or familial ALS was not confirmed in this study.