Mapping of Cis-Acting Expression Quantitative Trait Loci in Human Scalp Hair Follicles

In the study conducted by Herrera-Rivero et al., 100 male volunteers had their scalp hair follicles genetically analyzed to identify cis-acting expression quantitative trait loci (eQTLs). The researchers found 374 high-confidence eQTLs, with associated genes enriched for metabolic, mitotic, immune processes, and responses to steroid hormones. They replicated 68 associations in an independent dataset and identified three genomic regions related to hair shape and color, suggesting PADI3 as a potential gene influencing hair traits and possibly androgenetic alopecia. The study also highlighted differences in genetic regulation between frontal and occipital scalp regions and suggested the importance of mitochondrial function in hair biology. Pathways related to arginine metabolism, histone deacetylases, and vitamin C metabolism were differentially regulated in the frontal scalp, potentially affecting susceptibility to hair loss. Despite limitations such as a small sample size and the use of plucked hair follicles, the study provides insights into the genetic regulation within hair follicles and its impact on hair traits and disorders.