In my opinion the major message here is that there is a good deal of heterogeneity in all forms of ALS, even in specific subtypes of familial ALS such as this. This includes variability in penetrance, age and site of onset, comorbidities (for example dementia) and rate of progression. There are several possible reasons for this type of variability, including the specific site of each person's mutation within a given gene, possible modifier genes (for example kifap 3), and also possible environmental influences (for example exercise, lipid status).

Personally I think we now need to focus hard on this variability between patients....mother nature is trying to tell us something here! We could for example use new tools such as whole-genome microarray to compare fast and slow progressors. If we can understand this variability we may be able to shift patients' systems over to a more favorable phenotype even if we don't fully understand why it works.

View all comments by Richard Bedlack