At the urging of the National Human Genome Research Institute, the Defense Department proposed in 1999 that anyone who had served for 180 days be eligible for medical retirement, even if their health problem had a genetic component, said Barbara Fuller, assistant director for ethics at NHGRI, part of the National Institutes of Health.
But the Office of Management and Budget decided on the longer, 8-year term to conform with other military health and retirement guidelines, according to an OMB official.
Some genetic discrimination is unavoidable given the demands of military service, said Nunes, now a geneticist at Ohio State University.
"If you have achondroplasia -- if you're a dwarf -- you're not eligible for military service," he said. "If you have hereditary hearing loss, you're not eligible for military service. If you have color blindness, you're not eligible to fly an airplane. Obviously, there's genetic discrimination in the military, for good reason."
But Nunes said the armed forces' disability policy was flawed by a fundamental misunderstanding about the biology of inherited diseases.
Only in a few cases, such as Huntington's disease, does a specific mutation in a particular stretch of DNA guarantee the onset of illness.
In most cases, a faulty gene increases an individual's risk of developing a disease, but does not ensure it. Typically, an external event is necessary to trigger the onset of a medical condition.
Such was the case with an Army helicopter gunship pilot who was reassigned to desk duty after she became too pregnant to fly.
Dr. Melissa Fries, an Air Force geneticist who became involved in the case, said the pilot developed a blood clot in her leg -- a typical complication of pregnancy that is exacerbated by inactivity.
She was diagnosed with chronic thrombophlebitis, a condition that disqualified her from flying. The pilot, who declined to discuss her case, decided to retire from the Army.
As part of her medical work-up, doctors discovered she had a genetic mutation for Factor V Leiden, which is found in 5% of Caucasians and increases their risk of developing blood clots.
An Army physical evaluation board, which determines disability benefits, denied her claim because of the mutation.
Her military doctors were stunned since her thrombophlebitis was probably caused by her pregnancy and desk job. They downplayed the role of her mutation because 99% of Factor V Leiden carriers never develop blood clots.
