26 September 2007

Huntington's Disease Sufferers Get Reproductive Boost

by Kate Melville

People with Huntington's disease have more children than the general population because they are healthier during their peak reproductive years, finds a new study from Tufts University. Previously, it was believed that people with Huntington's disease have more children because of behavioral changes associated with the disease that lead to sexual promiscuity, but the new study, in the journal Medical Hypothesis, puts the kibosh on that theory.

"Huntington's is a disease that may have beneficial health effects on people early in life, but dire health costs later when symptoms express themselves," said Tuft's Philip T. Starks. "Ironically, these early health benefits may contribute to an increased prevalence of the disease." Huntington's disease is a genetic disease involving degeneration of the central nervous system (CNS), leading to uncontrolled muscle movements, emotional instability and dementia.

The new study focused on the tumor suppressor protein p53, which maintains normal cell growth and is found at levels above normal in Huntington's sufferers. At these elevated levels, p53 appears to increase resistance to cancer by causing cancerous cells to destroy themselves. Previous research has linked increased production of p53 to the mutant form of the Huntington (htt) protein that is found in the CNS of individuals with the disease. In this new hypothesis, the Tufts researchers suggest that p53 not only reduces the incidence of cancer in those affected by Huntington's disease but by improving overall health may also contribute to increased offspring production.

In their alternative hypothesis, the Tufts researchers suggested that individuals affected with Huntington's have better health earlier in life at the time when their fertility is highest. "We've raised the possibility that the high birth rates are a result of better health," explained Starks. "We know that healthy people have more offspring than those who are sick."

Starks suggested that one key factor behind these health benefits may be p53, and pointed to a 1999 study by doctors at the Danish Huntington Disease Registry at the University of Copenhagen that found lower age-adjusted cancer rates for individuals affected by Huntington's. "Research has shown that individuals with Huntington's produce higher levels of cancer-suppressing p53, and we hypothesize that they may also reap the health benefits associated with a generally more vigilant immune system," concluded Starks.

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Source: Tufts University