Pop Quiz #189

The correct answer is A. Peptidyl arginine deiminase, type III (PADI3).

This image shows a scarring alopecia, consistent with CCCA, centrifugal cicatricial alopecia. This disorder is associated with genetic mutations in peptidyl arginine deiminase, type III (PADI3), an enzyme involved in hair shaft formation.

Copper-transporting-P-type ATPase 7A (ATP7A) is mutated in Menkes Kinky hair, which is associated with pili torti & trichorrhexis nodosa. Keratin 81 (K81), along with K83, K86, and desmoglein 4, are mutated in monilethrix. This is characterized as beaded hair, with alternating normal thickness with constrictions. ATP-dependent DNA helicase (ERCC2 and ERCC3) is mutated in Trichothiodystrophy. This is characterized by a “tiger tail” abnormality (alternating light and dark bands).


Malki L, Sarig O, Romano MT, et al. Variant PADI3 in central centrifugal cicatricial alopecia. N Engl J Med. 2019;380(9):833-841. URL: https://pubmed.ncbi.nlm.nih.gov/30763140/