Scientists sort through 'junk' to unravel a genetic mystery

In 1965, when her 10-month-old son, David, started having seizures, Joan Stokes's excitement at being a first-time mother gave way to terror.

"I couldn't imagine what was wrong," she said.

The pediatrician was equally baffled. David's condition was not a result of a bacterial infection -- it failed to respond to antibiotics -- and tests for an array of common genetic disorders came back negative.Suspecting there was a problem with the parathyroid glands, small glands in the neck that ordinarily regulate calcium metabolism, doctors at St. Louis Children's Hospital gave David high doses of vitamin D to raise his blood calcium to normal levels.

The results were immediate and startling: David's seizures stopped, and unlike many of his male forebears, he grew and thrived, coasting through childhood without significant developmental delays.

A second afflicted son, born two years later, did similarly well on the vitamin D treatment.

Still, the genetic cause of the boys' rare disorder, known as X-linked recessive hypoparathyroidism, remained a conundrum. Michael Whyte of Washington University, one of the Stokes children's doctors, was determined to locate the chromosomal source of the illness.

"There were only two families in the world with this disease, both from eastern Missouri, so we knew the explanation was going to be highly unusual," he said.

More than 30 years after David's extraordinarily rare disease was diagnosed, Dr. Whyte and his longtime collaborator, Dr. Rajesh Thakker of Oxford University, have come a crucial step closer to isolating a biological culprit, finding specific chromosomal abnormalities associated with X-linked hypoparathyroidism.

•	Scientists sort through 'junk' to unravel a genetic mystery The New York Times, Tuesday, Feb. 7, 2006 Byline: Elizabeth Svoboda