It is a genetic disorder affecting the hair and occasionally the skin. Patches of alopecia may be present. It does not belong to the group of ectodermal dysplasias. The onset of the disease is at birth or within the first 2 years of life. In some cases, the symptoms may improve at puberty or during pregnancy; in other cases, the symptoms may remain the same throughout life.
Monilethrix Syndrome: Brittle, dry hair in a teenager with monilethrix. The eyebrows and eyelashes are also affected.
The exact incidence remains unknown. It affects males and females in equal numbers. The onset of the disease is at birth or by the age of 2 years.
It is believed inherited as 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.
Other conditions to be considered
Alopecia Areata Syndrome: Rare medical condition characterized by the progressive loss of hair. Children affected with this disorder tend to have a more severe evolution that those with an adult onset. The exact cause of Alopecia Areata is not known.
Pseudomonilethrix Syndrome: Extremely rare disorder characterized by sparse, dry, and brittle hair that breaks easily. Alopecia is a common finding in children. It is believed inherited as an autosomal dominant genetic trait.
Trichorrhexis Nodosa Syndrome: It is a condition where hair breaks and splits easily. It is associated with alopecia.
R: Hair loss in children. Curr Probl Dermatol
B: What syndrome is this? Monilethrix syndrome. Pediatr Dermatol
FW: Monilethrix: An ultrastructural study. J Cutan Pathol