Monilethrix

A rare genetic disorder affecting hair structure

Classification
External resources

Monilethrix is a rare genetic disorder that affects the structure of the hair shaft, leading to hair fragility and breakage. The condition is characterized by a distinctive beaded appearance of the hair, which is due to periodic narrowing of the hair shaft. This article provides an overview of the causes, symptoms, diagnosis, and management of monilethrix.

Causes

Monilethrix is primarily caused by mutations in the KRT81, KRT83, and KRT86 genes, which encode for type II hair keratin proteins. These proteins are essential components of the hair shaft, providing structural integrity and strength. Mutations in these genes lead to the abnormal formation of the hair shaft, resulting in the characteristic beaded appearance.

The condition is usually inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene from an affected parent can cause the disorder. However, there are also cases of autosomal recessive inheritance, where two copies of the mutated gene are necessary for the condition to manifest.

Symptoms

The primary symptom of monilethrix is the presence of fragile, brittle hair that breaks easily. The hair often appears beaded or segmented, with alternating nodes and constrictions along the shaft. This beaded appearance is most commonly observed on the scalp, but it can also affect other areas of the body, such as the eyebrows, eyelashes, and body hair.

Individuals with monilethrix may experience alopecia, or hair loss, due to the fragility of the hair. The severity of hair loss can vary widely among affected individuals, ranging from mild thinning to significant baldness.

Diagnosis

Diagnosis of monilethrix is typically based on clinical examination and the characteristic appearance of the hair under a microscope. A trichogram, or hair analysis, can reveal the beaded structure of the hair shaft, confirming the diagnosis.

Genetic testing can also be performed to identify mutations in the KRT81, KRT83, or KRT86 genes, providing a definitive diagnosis. This is particularly useful for confirming the diagnosis in atypical cases or for genetic counseling purposes.

Management

There is currently no cure for monilethrix, and management focuses on minimizing hair damage and improving cosmetic appearance. Gentle hair care practices, such as avoiding harsh chemicals and heat styling, can help reduce hair breakage.

In some cases, topical treatments such as minoxidil may be used to promote hair growth, although their effectiveness can vary. Patients are often advised to use mild shampoos and conditioners to maintain hair health.

Prognosis

The prognosis for individuals with monilethrix varies. Some individuals may experience improvement in hair growth and strength with age, while others may continue to have fragile hair throughout their lives. The condition does not affect overall health or life expectancy.

Related pages

• Hair disorders
• Genetic disorders
• Keratin
• Alopecia