Imagine being afraid to shake someone's hand, or to simply hold hands with a sweetheart. Beyond just embarrassing, "sweaty palms" syndrome is often a debilitating disorder that can affect one's work and life.
A new UCLA study in the February issue of the Journal of Vascular Surgery shows strong evidence that sweaty palms syndrome is genetic. It may be caused by a dominant gene -- indicating that family members of those who have the disorder may suffer from it more than has been previously reported.
"Traditionally, this syndrome was thought of as stress-related and has not been taken seriously by the medical community," said Dr. Samuel S. Ahn, principal investigator and professor, UCLA Division of Vascular Surgery. "This is one of the first studies helping to support that 'sweaty palms' is a real physiological disorder that can be passed from generation to generation."
According to Ahn and his collaborators in the UCLA Department of Human Genetics, the study indicates that as much as 5 percent of the population may be at risk for some form of hyperhidrosis, commonly known as sweaty palms syndrome, which causes excessive sweating, most often in the hands and feet. Less than 1 percent of the population was previously thought to be affected.
"Hyperhidrosis can truly affect one's life and career, such as a police officer dropping a gun and having a suspect literally slip away, or a fireman not being able to pull a hose or a banker unable to handle money due to severely sweating palms," Ahn said.
UCLA researchers took detailed family histories from 49 patients with hyperhidrosis and found that two-thirds (65 percent) reported family recurrence of the disorder, compared with zero percent in the control group.
Although the disorder appears to be inherited in a dominant fashion, the possible genes involved may not always cause hyperhidrosis. If one parent has the disorder, the study found that children have a 28 percent risk of also having hyperhidrosis, whereas the risk would be 50 percent if the gene produces the disorder directly. This indicates that other genes may also be necessary for hyperhidrosis to develop. If a child has the disorder, 14 percent of parents have it too.
"The strong inheritance pattern and large number of people with family recurrence of the disorder indicate that hyperhidrosis may be caused by a dominant gene," Ahn said. He adds that the disorder does not appear to be related to sex or ethnicity.
The next step, according to Ahn, is to test the DNA of people with hyperhidrosis and begin the process to of trying to identify genes that cause the problem.
Ahn's interest in pursuing this study began when a former patient of his told him that her six-week old infant also had hyperhidrosis. Ahn then realized the possibility that hyperhidrosis may be inherited and not environmentally related to stress.
Hyperhidrosis is caused by the sympathetic nerve, which governs the nervous system's "fight or flight" response. The sympathetic nerve causes blood vessel contraction in the hands and/or feet, leaving the extremities cold and sweaty. In people with hyperhidrosis, the perspiration is often excessive and continuous.
Treatment for hyperhidrosis of the hands now includes a minimally invasive surgery procedure, thorascopic sympathectomy, where a surgeon will snip the sympathetic nerve connected to the hands. Since the sympathetic nerve is not involved in motor skills or sensation, says Ahn -- who is a pioneer of the procedure -- the surgery simply stops the ability of the nerve to create hyperhidrosis. The procedure at UCLA has been 100 percent successful.
The study was funded by the California Vascular Research Foundation.