Characterization of X-Linked Hypohidrotic Ectodermal Dysplasia Hair and Sweat Gland Phenotypes Using Phototrichogram Analysis and Live Confocal Imaging

In a study conducted on May 17, 2013, researchers used phototrichogram analysis and live confocal imaging to examine the hair and sweat gland phenotypes of 12 males with X-linked hypohidrotic ectodermal dysplasia (XL-HED) and 13 unaffected control males. The study revealed that individuals with XL-HED had a significant absence of sweat ducts, with a median of 0 sweat ducts compared to 115 in controls, and were unable to produce sweat. Hair analysis showed that XL-HED subjects had fewer terminal hairs, a lower total hair count, reduced hair thickness, slower hair growth rate, fewer follicular units, and fewer hairs per follicular unit. Despite these differences, the percentage of terminal hairs in the anagen phase was similar between both groups. The study concluded that XL-HED is associated with a distinct lack of sweat ducts and a sparse hair phenotype, which is not directly related to the mechanisms of androgenetic alopecia. The findings are important for the development and evaluation of treatments for XL-HED, although no clear genotype-phenotype correlations were established, possibly due to the small sample size.