Scientists are narrowing in on two regions of the human genome that could be responsible for ALS (amyotrophic lateral sclerosis), also known as Lou Gehrig’s disease.
ALS is a neurodegenerative disorder that weakens muscles and paralyzes patients within three years of onset, and has no known cure. The available drug treatment delays progression by only three to five months.
Despite several attempts to find genetic variations associated with the sporadic form of the disease (which accounts for 95% of ALS cases), no association has been found.
A team of researchers from Netherlands, Van Es et al., analyzed the genes of nearly 20,000 people of European descent, including 5,000 ALS patients. Their results, published online this week in Nature Genetics, identified several genetic variations on two chromosomes suspected to affect ALS and other neurological functions.
The study revealed that each copy of the C version of rs12608932, a SNP on chromosome 19, is associated with a 1.2 times increased odds of ALS compared to having two copies of A. This SNP is found near UNC13A, a gene that may be involved in the function of motor neurons, which degenerate and die in ALS patients.
Each copy of the T version SNP rs2814707, located on chromosome 9, is associated with a 1.16 times increased odds of ALS compared to having two copies of C. This SNP was found in a region of the genome previously associated with the rare familial (non-sporadic) version of ALS. Researchers also found an association between the disease and a third SNP located very close to rs2814707.
There is increasing evidence that ALS belongs to a broader spectrum of neurodegenerative disorders, including Parkinson’s disease, so researchers speculate that genetic associations with ALS may also lead to clues about other disorders of the nervous system.
(Note: A previous genetic association listed in 23andMe’s ALS Research Report, which provides information about lower-impact and preliminary research results, was not replicated in this study.)
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