Uncombable hair syndrome Q84.1

Rare, non-syndromic, harmless hair anomaly characterized by so-called furrow hair, which is only cosmetically disturbing. Uncombable hair syndrome (UHS), also known as "pili trianguli et canaliculi" or "cheveux incoiffables", occurs in children and improves with increasing age. UHS is characterized by dry, frizzy, shaggy and often blond hair that cannot be combed straight. To date, both non-hereditary and familial cases of UHS with autosomal dominant and recessive inheritance have been described.

Biallelic mutations have been detected in the following genes (Basmanav FB et al. 2016):

• PADI3 (peptidylarginine deiminase 3)
• TGM3 (transglutaminase 3)
• TCHH (trichohyalin)

The two enzymes PADI3 and TGM3 are responsible for post-translational protein modifications. Their target structural protein TCHH (trichohyalin) is involved in hair shaft formation (see also.

Hair that is rough to the touch, dry, frizzy, hard, sticks out disorderly from the scalp and therefore cannot be styled, usually light-colored, silvery shimmering hair. Brushing and combing are impossible. Eyebrows, eyelashes and body hair are normal. The hair appears shimmering in the light and is reminiscent of Pili torti or Pili pseudoanulati.

In light microscopy, the cross-section of the hair shaft is rather triangular or kidney-shaped (normal: round or oval). The hair shaft anomaly is best shown by means of the so-called shrink tube technique.

Pili torti (circumscribed foci with peculiarly shimmering (due to different reflections of light in the twisted areas), twisted, dry, brittle, thin hairs that rarely grow longer than 4-6 cm).

Kinky hair disease

Hypotrichosis congenita hereditaria generalisata

Monilethrix syndrome (rare, hereditary growth disorder of the hair with periodic caliber fluctuation of the hair shaft and breakthrough disorders/ Monile = pearl necklace)

Anhidrotic ectodermal dysplasia (rarified scalp hair, complex malformation syndrome with variably occurring dental anomalies with malpositioning, sensory deafness, syndactyly, pincer nails, mental retardation, short stature, photophobia and strabismus).

Hidrotic ectodermal dysplasia (very sparse, thin, short, brittle, dry hair up to total alopecia; sparse or absent axillary and pubic hair, sparse cilia, thinned eyebrows in the two lateral thirds, hyperkeratosis of the palms and soles. Knuckle pads are described on the fingers)

Central centrifugal cicatricial alopecia (only in women of African descent)

1. Basmanav FB et al (2016) Mutations in Three Genes Encoding Proteins Involved in Hair Shaft Formation Cause Uncombable Hair Syndrome. Am J Hum Genet 99:1292-1304.
2. Brown-Falco O et al (1982) On the syndrome: uncombable hair. Dermatologist 3: 366-372
3. Dupré A, Rochiccioli P, Bonafé JL (1973) "Cheveux incoiffables": anomalie congenitale des cheveux. Bull Soc Franc Dermatol Syph 80: 111-112
4. Dupre A, Bonafe JL (1978) A new type of pilar dysplasia. The incompatible hair syndrome with pili trianguli et canaliculi. Arch Dermatol Res 261: 217-218
5. Hicks J, Metry DW, Barrish J, Levy M (2001) Uncombable hair (cheveux incoiffables, pili trianguli et canaliculi) syndrome: brief review and role of scanning electron microscopy in diagnosis. Ultrastruct Pathol 25: 99-103
6. Ludwig E (1987) Pili canaliculi, a type of uncombed hair. Dermatologist 38: 727-732