Genetics of sporadic ALS

The only known gene to be involved in ALS is the CuZn-superoxide dismutase (CuZn-SOD) gene. Since 1993, 89* disease-associated mutations have been fou nd in this gene, 14 of them in cases with apparently sporadic ALS. Most fre quent are the D90A (most often with recessive inheritance, but a few with d ominant inheritance) and the I113T (dominant inheritance with variable pene trance). Statistical and genealogical evidence suggest that quite a number of diagnosed sporadic cases may in fact be familial cases in pedigrees with very low disease penetrance.