An unusual and uncommon psychiatric disorder that compels people to pull out their hair is now thought to be caused by a mutant gene.
Scientists at Duke University Medical Center say they have identified gene mutations that causes the disorder trichotillomania which affects between 3 percent and 5 percent of the population.
Trichotillomania is considered an impulse control disorder and sufferers have noticeable hair loss or patches of baldness, but they often disguise their habit and the disorder often goes undiagnosed and untreated.
The disorder is often accompanied by other psychiatric conditions, such as anxiety, depression, obsessive compulsive disorder or Tourette syndrome, which are better known than the hair-pulling behavior.
The research team found two mutations in a gene called SLITKR1 that were implicated in trichotillomania patients but say the mutations account for only a small percentage of trichotillomania cases.
Nevertheless the findings are significant because they expose a biological basis for mental illnesses which are as a rule blamed on a person’s upbringing or life experiences.
Lead study investigator Stephan Züchner, M.D., assistant professor of psychiatry and researcher at the Duke Center for Human Genetics says psychiatric conditions carry negative perceptions in society.
Züchner believes if science can demonstrate such disorders have a genetic origin, diagnosis can be improved and new therapies developed which will in turn reduce the stereotypes associated with mental illness.
At present there is no specific treatment for trichotillomania, although it is sometimes successfully managed with drugs used for depression and anxiety disorders.
The Duke scientists studied 44 families with one or more members who had trichotillomania.
The researchers studied SLITRK1 because it was linked last year to a related impulse-control disorder called Tourette syndrome, which causes repetitive behaviors such as blinking, throat-clearing or shouting obscenities.
The parent of one Tourette patient carried the SLITRK1 mutation but displayed only symptoms of trichotillomania, not Tourette.
When they looked further the team found two mutations in the SLITRK1 gene among some individuals with trichotillomania but not in their unaffected family members.