Description
Uncombable hair syndrome is a condition that is characterized by dry, frizzy hair that cannot be combed flat. This condition develops in childhood, often between infancy and age 3, but can appear as late as age 12. Affected children have light-colored hair, described as blond or silvery with a glistening sheen. The hair does not grow downward but out from the scalp in multiple directions. Despite its appearance, the hair is not fragile or brittle, and it grows at a normal or slightly slower rate. Only scalp hair is affected in uncombable hair syndrome.
For unknown reasons, this condition usually improves over time. By adolescence individuals with uncombable hair syndrome have hair that lies flat and has normal or nearly normal texture.
Frequency
The prevalence of uncombable hair syndrome is unknown; at least 100 cases have been described in the scientific literature. There are likely more people who are undiagnosed because adults who seem unaffected may have had uncombable hair syndrome in childhood.
Causes
Uncombable hair syndrome is caused by mutations in the PADI3, TGM3, or TCHH gene. These genes provide instructions for making proteins that help give structure to the hair strand (shaft).
The proteins produced from the PADI3 and TGM3 genes modify the protein produced from the TCHH gene, known as trichohyalin. The modified trichohyalin can attach (bind) to other trichohyalin proteins and to molecules called keratin intermediate filaments to create organized cross-links. These links form dense networks that provide structure to the hair shaft and give it a cylindrical shape.
PADI3, TGM3, or TCHH gene mutations likely lead to the production of proteins with little or no activity. As a result, the shape of the hair shaft is altered. Instead of having a cylindrical shape, it has a triangular, heart-like, or flat cross-section. Sometimes all of these irregular shapes can occur along the length of a single strand of hair. Because of the angular shape of the hair shaft, the hair will not lie flat. In children with uncombable hair syndrome, 50 to 100 percent of their strands of hair have an irregular shape. Additionally, the abnormal hair reflects light differently than normal hair, accounting for its glistening sheen.
Some people with uncombable hair syndrome do not have an identified mutation in one of these three genes. The cause of the condition in these individuals is unknown.
Inheritance
When uncombable hair syndrome is caused by mutations in the PADI3, TGM3, or TCHH gene, it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
In other cases, uncombable hair syndrome appears to be inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In these cases an affected person usually inherits the mutation from one affected parent, although the associated gene is unknown.
In still other cases of uncombable hair syndrome, the inheritance pattern is unknown.
Other Names for This Condition
- Cheveux incoiffables
- Pili trianguli et canaliculi
- Spun glass hair
- UHS
- Unmanageable hair syndrome
References
- Calderon P, Otberg N, Shapiro J. Uncombable hair syndrome. J Am Acad Dermatol. 2009 Sep;61(3):512-5. doi: 10.1016/j.jaad.2009.01.006. Citation on PubMed
- Rieubland C, de Viragh PA, Addor MC. Uncombable hair syndrome: a clinical report. Eur J Med Genet. 2007 Jul-Aug;50(4):309-14. Epub 2007 Apr 11. Citation on PubMed
- Ü Basmanav FB, Cau L, Tafazzoli A, Méchin MC, Wolf S, Romano MT, Valentin F, Wiegmann H, Huchenq A, Kandil R, Garcia Bartels N, Kilic A, George S, Ralser DJ, Bergner S, Ferguson DJP, Oprisoreanu AM, Wehner M, Thiele H, Altmüller J, Nürnberg P, Swan D, Houniet D, Büchner A, Weibel L, Wagner N, Grimalt R, Bygum A, Serre G, Blume-Peytavi U, Sprecher E, Schoch S, Oji V, Hamm H, Farrant P, Simon M, Betz RC. Mutations in Three Genes Encoding Proteins Involved in Hair Shaft Formation Cause Uncombable Hair Syndrome. Am J Hum Genet. 2016 Dec 1;99(6):1292-1304. doi: 10.1016/j.ajhg.2016.10.004. Epub 2016 Nov 17. Citation on PubMed or Free article on PubMed Central
Medically Reviewed by Dan Brennan, MD on February 22, 2022 Uncombable hair syndrome, or UHS, is a rare condition that typically causes dry, frizzy hair that you can’t comb flat. It usually emerges before age 3 but may show up as late as age 12. It
appears to be rare; scientists know of only about 100 cases. But there are likely many more cases that doctors don’t diagnose because the condition often goes away in childhood. Other names for the condition include: Symptoms show up between 3 months and 12 years of age in
children with straw- colored or blond-silvery hair. The hair color may develop over time. You typically have a normal amount of hair, but it often grows more slowly. The hair stands out from the scalp and grows in different directions. It may be impossible to comb it flat against the scalp. (The condition only affects the hair of the scalp, not hair on other parts of the body.) The hair is not usually more fragile than in people who don’t have the condition, but
constant brushing or grooming may be more likely to cause damage. UHS usually occurs on its own, but in some cases it may be linked to other diseases that require medical treatment. These diseases might include: It’s important to find out whether UHS is linked to these and other conditions so that you and your health care team can help form a treatment plan if you need
one. Other symptoms that may happen in some UHS cases include: UHS typically happens on its own because of changes or “mutations” in three genes that give instructions on how to make strands of hair on your scalp. These genes are: You typically inherit these gene mutations when both your parents carry a copy of the mutation, though your parents may not have the condition (autosomal recessive inheritance). Scientists think that some people may also get the condition when only one parent carries a mutation (autosomal dominant inheritance). These mutations change the shape of the hair shaft from tubular to more angular like a triangle or heart shape. This changes the
texture, makes it harder to brush, and causes the light to reflect in a way that gives the hair a certain color. In some cases, people get UHS without mutations in these genes. Scientists continue to study the cause of UHS in these cases. Your doctor will look for typical symptoms of UHS like hair color, texture, and wild growth patterns. They will look at the hair shaft under a microscope
for the telltale triangular or kidney shape with a long groove that runs along its length. There soon may be genetic tests available for UHS. There is no cure for UHS, but it usually gets better or goes away completely around the start of puberty. Doctors typically suggest that you are gentle with your hair if you have UHS. That means: Some people think that biotin supplements can improve the appearance of your hair if you have UHS. More studies are needed to be sure. Talk to your doctor before you start yourself or your child on any type of medication or supplement. UHS is not serious on its own, though in rare cases, it may be a symptom of a more serious condition, which is why you should talk to your doctor if you suspect UHS in yourself or your child. In general, you won’t need treatment of any sort and the condition will go away on its own in the teen years.What Are the Symptoms?
What Causes It?
How Do Doctors Diagnose UHS?
How Do Doctors Treat UHS?
Outlook