He is famous for stealing Lou Gehrig's life, Stephen Hawking of its mobility and voice, but just how amyotrophic lateral sclerosis (ALS) destroys motor neurons in the brain and spinal cord remains a mystery. Now scientists converge an explanation, at least for a fraction of ALS cases caused by a mutation also associated with a kind of dementia. In cells with the mutation, the new work shows, pores in the membrane separating the nucleus and cytoplasm become blocked, preventing the vital molecules to pass through and creating a fatal cellular traffic jam. For now, the work applies only to the mutation dubbed C9ORF72 a stutter-DNA in which a short nucleotide sequence, GGGGCC is repeated hundreds of thousands of times in a gene on chromosome 9. Neither do multiple laboratories reporting results this week agree on exactly what caps the nuclear pores and how cells die. Yet many in the field call it the work of a major breakthrough, and say the findings could point to new therapies and a new mechanism of neurodegeneration.
To read the full article, see August 28 issue of Science .
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