Bad hair days may have genetics to blame

The first gene mapping study on human scalp hair whorls not only shows that hair whorl direction has a genetic basis, but also that it is affected by multiple genes. Four associated genetic variants that are likely to influence hair whorl direction are identified, as reported in the Journal of Investigative Dermatology.

As an easily observed human trait, scalp hair whorl pattern is typically defined by the whorl number (single or double whorl) and whorl direction (e.g., clockwise, counterclockwise, or diffuse). Because atypical whorl patterns have been observed in patients with abnormal neurological development, understanding the genetic basis of whorl patterns may help unravel important biological processes.

The first genome-wide association study (GWAS) on human scalp hair whorls was performed among 2,149 Chinese individuals from the National Survey of Physical Traits cohort, followed by a replication study in 1,950 Chinese individuals from the Taizhou Longitudinal Study cohort.

The study identifies four associated genetic variants (at 7p21.3, 5q33.2, 7q33, and 14q32.13). These genetic variants are likely to influence hair whorl direction by regulating the cell polarity of hair follicles, with cranial neural tube closure and growth also potentially playing a role.

Reference: “GWASs Identify Genetic Loci Associated with Human Scalp Hair Whorl Direction,” by Junyu Luo, He Huang, Hui Qiao, Jingze Tan, Wenyan Chen, Manfei Zhang, Andrés Ruiz-Linares, Jiucun Wang, Yajun Yang, Li Jin, Denis J. Headon, and Sijia Wang (https://doi.org/10.1016/j.jid.2022.11.026). It appears online in advance of the Journal of Investigative Dermatology, volume 143, issue 10 (October 2023), published by Elsevier