Uncombable Hair Syndrome

Uncombable hair syndrome (UHS), also known as spun-glass hair, unmanageable hair syndrome, cheveux incoiffables, or pili trianguli et canaliculi, is a rare genetic disorder of the hair shaft that primarily affects children. UHS only affects the hair on the scalp and is identified by a hallmark silvery-blond or straw-colored appearance. The hair strands stand out from the scalp in multiple directions and cannot be combed flat. UHS typically emerges between three months and 12 years of age and spontaneously resolves in adulthood. At least 100 cases of uncombable hair syndrome have been recorded in the literature; however, the true prevalence of UHS remains unknown as many adults may have had undiagnosed UHS in childhood.

The exact cause of UHS remains unknown. According to the Genetic and Rare Diseases Information Center (GARD), UHS is most likely caused by sporadic mutations in the genes PADI3, TGM3, and TCHH. These genes code for proteins involved in hair shaft formation. The proteins produced by the PADI3 and TGM3 genes modify a protein produced by the TCHH gene, called trichohyalin. The trichohyalin protein attaches to other trichohyalin proteins through a type of cross-linking protein known as keratin intermediate filaments to create dense networks that provide structure to the hair shaft and give it a cylindrical shape. Mutations in these genes can lead to irregular hair shapes, such as triangular or kidney-shaped, preventing the hair from growing in a cylindrical shape or lying flat.

In some cases, UHS may be acquired through autosomal recessive inheritance (i.e., having two affected genes, one from each parent); however, autosomal dominant inheritance (i.e., having one affected gene from one parent) may also occur due to the large number of genes involved in hair formation. UHS may also be linked to other genetic conditions, such as ectodermal dysplasias, Bork syndrome, and Angel-shaped phalangoepiphyseal dysplasia. 

UHS is characterized by a wide range of distinctive symptoms, including coarse and/or rough-textured hair, white and/or wooly hair, patchy alopecia, and abnormal hair morphology. Individuals with UHS may typically experience dry, frizzy hair that is resistant to smoothing or combing; shiny, light-colored hair that may appear silver, white, or blonde to light brown; and hair that is characterized by untamed growth in multiple directions. Not all individuals with UHS will encounter all these symptoms. For example, an individual with UHS may have naturally black hair that is uncombable. Although the appearance may suggest fragility, UHS hair is surprisingly resilient and maintains a growth rate that is largely within the normal range.

UHS is commonly diagnosed by a medical professional, such as a dermatologist, after gathering a comprehensive medical history and conducting a thorough physical examination. Visual inspection of the hair on the scalp may be effective in initiating the diagnosis of UHS due to the unique symptoms and characteristics of the hair structure. An electron microscope examination of the hair on the scalp may also be conducted for a detailed analysis of the hair structure. This diagnostic tool is crucial in the identification of UHS as well as investigating potential links to other genetic conditions if a genetic component is suspected. Genetic testing may also be used to confirm UHS diagnosis, which involves the collection of a blood sample to detect genetic mutations in the PADI3, TGM3 and/or TCHH gene.

While there is no established treatment for UHS, a gentle and effective hair care routine can be adopted to manage distinctive symptoms until spontaneous improvement occurs in adulthood. Avoidance of harsh chemical hair treatments, such as perms or hair dye, is advised as these may worsen symptoms and damage hair. Refraining from excessive brushing or combing and minimizing the use of heated hair styling tools, such as curling irons or blow dryers, may also be helpful. Regular haircuts and the use of soft brushes may also assist in hair maintenance.

Although the exact benefits and mechanism of action of biotin supplements in UHS have not been fully validated, some studies suggest a role in enhancing hair appearance and management. Individuals with UHS may also present with low self-esteem given their hair appearance and may benefit from consulting a mental health professional.

Uncombable hair syndrome (UHS)  is a rare genetic disorder of the hair shaft. UHS only affects the hair on the scalp and is identified by a hallmark silvery-blond or straw-colored appearance and the inability to comb hair flat. UHS typically emerges between three months and 12 years of age and spontaneously resolves in adulthood. UHS can be caused by mutations in the genes PADI3, TGM3, and TCHH; which can lead to irregular hair shapes and are typically sporadic but can be acquired through autosomal recessive inheritance and (less commonly) autosomal dominant inheritance. Individuals with UHS may typically experience dry, frizzy hair that is resistant to combing and shiny, light-colored hair. UHS is most commonly diagnosed through visual and/or electron microscope examination of the hair. While there is no established treatment for UHS, a gentle and effective hair care routine can be adopted to manage distinctive symptoms.