Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android

Genetic disorder affecting the hair and occasionally the skin; does not belong to the group of ectodermal dysplasias.


Brittle, dry hair in a teenager with monilethrix. The eyebrows and eyelashes are also affected.

Unknown. It is an autosomal dominant disorder. The cause of this disease seems to be a mutation in the genes responsible for the hair keratin, which has been mapped to 12q13.

Although the symptoms of these syndromes may resemble ectodermal dysplasia, monilethrix does not belong to this group. It is characterized by a beaded appearance of the scalp hair caused by periodic narrowing of the hair shaft. Phenotypically, this results in breakage of the hair (brittle, dry, lusterless look) and patchy alopecia. The onset is usually in infancy, and symptoms may ameliorate to a certain degree after puberty and during pregnancy. Hair outside of the scalp area (pubis, axilla, eyelashes, eyebrows) is occasionally affected. Some patients show signs of koilonychia and follicular keratosis. Over the years, skin atrophy may develop in affected areas.

These patients are otherwise healthy and do not require any specific anesthetic precautions.

Despontin K, Krafchik B: What syndrome is this? Monilethrix syndrome. Pediatr Dermatol 10:192, 1993.  [PubMed: 8346120]
Ito M, Hashimoto K, Yorder FW: Monilethrix: An ultrastructural study. J Cutan Pathol 11:513, 1984.  [PubMed: 6520260]
Stevens HP, Kelsell DP, Bryant SP: Linkage of monilethrix to the trichocyte and epithelial keratin gene cluster on 12q11-q13. J Invest Dermatol 106:795, 1996.  [PubMed: 8618025]

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.