This morning kicked off with a session about genes and phenotypes. The six talks focused on trends in the development of MND in different groups of people and involved an international panel of researchers from the UK, China, Taiwan, Chile and Brazil.
In his talk, Dr Andrew Douglas, based at the University of Oxford, UK, discussed his research to understand how often people who carry a particular gene change, in this case the C9orf72 repeat expansion, actually develop disease. The C9orf72 repeat expansion is the most common genetic change found in people with MND or FTD of white European ancestry. But how likely it is that someone with a change in this gene develops MND isn’t very well understood.
Dr Douglas’s research involved families affected by the C9orf72 repeat expansion gene change. For each family, the researchers looked at family trees and assigned each family a score based on how many relatives had the disease vs how many didn’t, their ages and how likely each relative was to carry the genetic change, based on inheritance patterns. The researchers then number-crunched information from 52 families.
Of the 1,110 people, there was enough information to include 758 in the analysis. Of the 177 people diagnosed with a neurodegenerative disease:
- 74% had ALS, the most common form of MND
- 15% had FTD
- 7% had Alzheimer’s disease
- 4% had Parkinson’s disease
Looking at all the families together, the researchers found people with a change in the C9orf72 gene had a 64% chance of developing a neurodegenerative disease by the age of 80. However, this varied between individual families; in some, the risk was as low as 27%, and in others, as high as 100% (everyone who had the change in that family developed a neurodegenerative disease). There was a strong dominance of MND over other diseases. Dr Douglas explained the data points towards there being inherited (genetic) factors in some families that make those with the C9orf72 gene change more likely to get MND specifically, rather than another neurodegenerative disease. In the future, researchers will look more closely at what these factors might be that affect each person’s risk.
The research presented by Dr Douglas suggests families may be able to get personalised estimates of their disease risk, based on family history. Continued research will help make these predictions more accurate. In the future, the predictions could be applied more widely to other genetic forms of MND.
