Decoding disease

Efforts to solve the mysteries of various diseases has entered a new phase as scientists work to read the entire genetic code of patients. In today’s Health & Science section my colleague Faye Flam reports on geneticist James Lupski who had his own genetic code sequenced to discover what had caused him to develop Charcot-Marie-Tooth (CMT) syndrome.

Here is some of what my colleague wrote:

No one had found the gene responsible for CMT, which can cause muscle weakness in the hands and legs.Lupski, of the Baylor College of Medicine, said his symptoms began at 15, when he began stumbling. Walking soon became difficult.

The disease is usually recessive, which explained why neither of his parents had it. An older sibling had developed similar problems, he said, leading doctors to begin looking for a genetic disorder. But CMT syndrome can be easily misdiagnosed since symptoms occur in other neuropathies and may not appear until people are in their 50s. About 40 genes had been linked to the disease, but Lupski had tested negative for mutations in all of them.

Then he had his entire genetic code read. That revealed that Lupski had inherited two abnormal copies of a gene called SH3TC2, which is associated with the nervous system.

Lupski coauthored a paper on his own case, appearing online last week in the New England Journal of Medicine. His case demonstrates how individual genetic sequencing might become an important diagnostic tool for identifying hundreds of possible genetic diseases.

And last week, The New York Times reported how the reduced cost for reading the genetic code of one patient (about $50,000 a person) has opened a new front in finding the root causes of major diseases such as diabetes, heart disease and cancer.