This piece is a touching story about young husband and wife researchers at the Broad Institute working on the genetics of the prion gene, PRF, and its mutation at Chromosome 20 p 13. The wife of his team has one of the mutations that is usually fatal. In some ways, the genetics resembles Huntington’s disease, because a few sequence repeats are widely found in humans, but as the number increases from six to 14, more serious-disease becomes most-serious. This team has identified three mutations that are benign, three that represent greater risk, and four that are fatal, often in middle age. Perhaps most curiously, the prion gene has no known function.  MORE