Case Reflects Influence Ethnic Differences Have on Genetic Medicine

SAN JOSE, Calif. — Something seemed odd with the families Dr. Nipavan Chiamvimonvat and Dr. Kathryn Glatter wanted to help.

The heart specialists at the University of California-Davis were curious about two Chinese-American mothers diagnosed with inherited Long QT syndrome, a dangerous heart ailment. Both had been labeled with a particular form of Long QT after taking a test that compared their genes to standards developed from a group of whites.

But their symptoms didn’t match their genetic diagnoses. Chiamvimonvat and Glatter decided to start a new study that included genes from Asian-Americans.

Their work revealed that the original diagnosis was flawed — and had put the women and their families through years of the wrong medical care.

The women did have Long QT, but not the form originally suspected. One of the women had two small sons, who had both been screened previously with the wrong test. The elder boy, thought to share his mother’s Long QT gene, had been taking heart medication for years. His younger brother, deemed healthy, wasn’t being treated.

But the new test showed that the older son did not have the condition at all, and didn’t need heart medication. Instead, the younger son had inherited his mother’s Long QT gene — and should have been treated long ago.

“It was chilling,” Glatter said. “I cannot stress how important it is to have accurate matches when you are dealing with genetic issues. You need to make sure you are comparing apples to apples and oranges to oranges.”

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