Amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis is a devastating, relentlessly progressive neurodegenerative disease compromising lower and upper motor neurons, and resulting in death, usually from marked weakness of respiratory musculature (Haverkamp et al., 1995). The incidence of ALS is 1-2/100,000 and the prevalence is 4-6/100,000. Ninety percent of ALS cases are sporadic (sALS), while 10% are familial (fALS). The etiology of sALS is unknown, and no known pharmacotherapy has been demonstrated to significantly influence either disease progression or survival. A defect in the gene encoding copperzinc superoxide dismutase (SOD1) is present in 20% of fALS cases (Rosen et al., 1993). In sALS, the mean age of onset is 57 years and the median survival is approximately four years with younger patients surviving longer than older individuals. Males develop sporadic ALS more frequently than females (ratio 1.7:l). However, in older individuals the frequency of female involvement is increased and the ratio approaches 1:1 over the age of 65, which is similar to the ratio in fALS.