In about 90% of ALS cases, the person diagnosed is the only member of the family with the disease. These cases are called “sporadic ALS”. The cause of sporadic ALS is not well understood, but may be due to a combination of environmental and genetic risk factors.
Familial ALS is caused by a mutation. A mutation is a genetic change or abnormality in a particular gene. Sorting out which gene is to blame is complicated. Humans have about 50,000 genes, and in most people with familial ALS scientists have not yet identified which gene is responsible for causing ALS. What we do know is that in about 2 in 10 families with ALS, the disease is caused by a change in the superoxide dismutase, or SOD1, gene. Genetic changes in genes such as FUS and TDP-43 are the cause of ALS in an even smaller number of families with ALS, each accounting for approximately 1 in 20-25 families.
Most familial ALS, at least in the United States, is inherited in an “autosomal dominant” fashion. This means if one carries the gene, then there is a 50% chance of passing the gene onto one’s children. If you have a parent or sibling with ALS, there is a 50% chance that you also carry the genetic abnormality that can cause ALS.
Our Story… Our family, unfortunately fell in the 10% of cases that are considered “Familial ALS” (FALS) with a devastating loss of 6 family members:
- Hubert Burnside
- W.T Burnside
- Glenna Nutt
- Theresa Burnside
- Troy Burnside
- Sharon Teel