New gene involved in hair texture, density uncovered

The U.S. researchers have discovered a new gene involved in determining hair texture in humans, according to journal Nature Genetics to be published in March.

Their genetic analysis demonstrated that mutations in a gene, known as P2RY5, cause hereditary "woolly hair" -- hair that is coarse, dry, tightly curled and sparse. The paper about the findings will appear in the March edition of journal Nature Genetics.

"Our findings indicate that mutations in the P2RY5 gene cause hereditary woolly hair. This is significant as it represents the discovery of the first new gene whose primary function seems to be the determination of hair texture in humans," said lead author Angela M. Christiano at the Columbia University Medical Center.

"This genetic finding may inform the development of new treatments for excessive or unwanted hair, or potentially hair growth," Christiano added.

The genetic causes of hair texture in humans are largely unknown. Since research has shown that woolly hair was common among Pakistani families, Christiano and her colleagues set out to determine why this type of hair was specific to this group of people.

To identify a gene involved in controlling hair texture, the research team performed a genetic analysis of six families of Pakistani origin, who all shared hereditary woolly hair. The cause of hereditary woolly hair was found to be a mutation in the P2RY5 gene.

"The bulb region of plucked hairs from woolly hair patients showed irregular bending without attachment of the root sheath." the authors said.

They propose that mutations in P2RY5 most likely result in hair follicle disruptions, which then compromise its anchoring to the hair shaft and cause the abnormal bending of the bulb region, leading to woolly hair.

Christiano's discoveries have led to the identification of several genes controlling human hair growth. It remains to be determined whether common variants on the P2RY5 gene can also contribute to naturally occurring variations in hair texture between different human populations.

According to the researchers, P2RY5 is the first gene of a type known as a G-protein coupled receptor (GPCR) implicated in a human hair disorder, thereby making it possible to develop drugs that target this receptor.