At first, Matthew assumed the weakness in his knee was the sort of orthopedic nuisance that happens when you turn 30. It was weeks before he consulted a doctor, and months before it occurred to him that there could be a connection between his worsening limp and a cousin’s shoulder problem when they were kids. DNA testing confirmed it: Matthew, like his cousin, had a genetic form of dystonia, a condition where muscles contract uncontrollably. Their grandfather most likely had dystonia as well.
I’d met Matthew only a few months earlier, when he’d married my friend’s daughter, Olivia, in one of those hip old New York hotels with an elegant downtown vibe. Since I was the only genetic counselor of their acquaintance, they brought their questions to me. With their permission, I am sharing their story. I have changed their names to preserve their privacy.
Matthew was lucky. His was a mild version of DYT1 dystonia, and injections of Botox in his knee helped. But the genetic mutation can cause severe symptoms: contractures in joints or deformities in the spine....