But for the individual case, there may be several personal reasons why one might opt for predictive testing, such as life decisions like going on a round-the-world trip with a caravan before or after retirement (as reported by a 57-year old woman whose sisters both carried a SOD1 mutation and developed ALS by the age of 63 and 61 years respectively). This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.