Monilethrix

Monilethrix (also referred to as "Beaded hair") is a rare autosomal dominant hair disease that results in short, fragile, broken hair that appears beaded. It comes from the Latin word for necklace (monile) and the Greek word for hair (thrix).

Characteristics
The presentation may be of alopecia. Individuals vary in severity of symptoms. Nail deformities may also be present as well as hair follicle keratosis and follicular hyperkeratosis.

Cause and Genetics
Monilethrix is caused by mutations affecting the genes KRTHB1 (KRT81), KRTHB3 (KRT83), or KRTHB6 (KRT86) which code for type II hair cortex keratins. The disorder is inherited in an autosomal dominant manner. This means that the defective gene(s) responsible for a disorder is located on an autosome, and only one copy of the gene is sufficient to cause the disorder, when inherited from a parent who has the disorder.

Diagnosis
Monilethrix may be diagnosed with trichoscopy