As a writer for the Hair Sciences column for the prestigious Hair Transplant Forum International publication, Dr. Ratushny likes to stay up to date on the latest research on hair loss.  In this month’s blog, we explore new research that attempts to answer the question of why certain areas of the human body have hair while other areas do not.

If you compare the skin on the palms of your hands or soles of your feet to your arms and legs, what differences do you notice?  In most human beings, palms are hairless while most other areas of the body have hair of varying sizes, lengths, and color.  In their December 2018 publication in Cell Reports1 titled, “Regional Control of Hairless versus Hair-Bearing Skin by Dkk2,” Yaolin Song and colleagues demonstrate that the Dkk2 gene may play a key role in whether skin is determined to be hairless or hair-bearing.  The authors used a mouse model in which they were able to delete the Dkk2 gene and looked at the effects this would have on the plantar paw skin of mice, which is normally hairless.  Deletion of the Dkk2 gene resulted in ectopic hair formation in the normally hairless mouse paw.  This ectopic hair formation was mediated by the effects of Dkk2 on the WNT/β-catenin pathway, which is a signaling cascade responsible for hair follicle formation.  The authors postulate that these findings in mice will likely be relevant to humans since the role of the WNT/β-catenin pathway is evolutionary conserved.

An interesting area of future research is whether we can modify the Dkk2 pathway to help with the regeneration of fully functional skin with hair follicles following severe injuries such as burns.

  1. Song Y, Boncompagni AC, Kim SS, et al. Regional Control of Hairless versus Hair-Bearing Skin by Dkk2. Cell Reports. 2018 Dec 11;25(11):2981-2991.