Uncombable hair syndrome
Encyclopedia
Uncombable hair
syndrome, also known as Pili trianguli et canaliculi, Spun-glass hair, and Cheveux incoiffables, is a rare structural anomaly of the hair with a variable degree of effect. It was discovered in the 1970s. It becomes apparent from as little as 3 months to up to 12 years.
or straw-colored. It is disorderly, it stands out from the scalp, and cannot be combed flat. The underlying structural anomaly is longitudinal grooving of the hair shaft, which appears triangular in cross section. There usually is no family history, though the characteristic hair shaft anomaly can be demonstrated in asymptomatic family members by scanning electron microscopy. To be noticeable, 50 % of hairs must be affected by the structural abnormality. Improvement often occurs in later childhood. An autosomal dominant mode of inheritance has been suggested though an autosomal recessive pattern with varying degrees of penetrance
has also been noted. The stiffness of the uncombable hair has been reasoned to be due to the triangular form of the hair shaft in cross section. It has been suggested that the condition may result from premature keratinization of the inner root sheath.
, EEC syndrome (ectodermal dysplasia
, ectrodatyly and cleft lip/palate) and familial tricho-odonto-onychial ectodermal dysplasia with syndactyly
. However unlike these conditions, uncombable hair syndrome alone is not associated with physical, neurologic, or mental abnormalities.
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
syndrome, also known as Pili trianguli et canaliculi, Spun-glass hair, and Cheveux incoiffables, is a rare structural anomaly of the hair with a variable degree of effect. It was discovered in the 1970s. It becomes apparent from as little as 3 months to up to 12 years.
Presentation
The hair is normal in quantity and is usually silvery-blondBlond
Blond or blonde or fair-hair is a hair color characterized by low levels of the dark pigment eumelanin. The resultant visible hue depends on various factors, but always has some sort of yellowish color...
or straw-colored. It is disorderly, it stands out from the scalp, and cannot be combed flat. The underlying structural anomaly is longitudinal grooving of the hair shaft, which appears triangular in cross section. There usually is no family history, though the characteristic hair shaft anomaly can be demonstrated in asymptomatic family members by scanning electron microscopy. To be noticeable, 50 % of hairs must be affected by the structural abnormality. Improvement often occurs in later childhood. An autosomal dominant mode of inheritance has been suggested though an autosomal recessive pattern with varying degrees of penetrance
Penetrance
Penetrance in genetics is the proportion of individuals carrying a particular variant of a gene that also express an associated trait . In medical genetics, the penetrance of a disease-causing mutation is the proportion of individuals with the mutation who exhibit clinical symptoms...
has also been noted. The stiffness of the uncombable hair has been reasoned to be due to the triangular form of the hair shaft in cross section. It has been suggested that the condition may result from premature keratinization of the inner root sheath.
History
A possible case of uncombable hair syndrome was reported in 1912 by A.F. Le Double and F. Houssay. The syndrome was described in 1973 by A. Dupré, P. Rochiccioli and J.L. Bonafé, who named it "cheveux incoiffables". Later that year it was independently described as "spun-glass hair" by J.D. Stroud and A.H. Mehregan.Similar conditions
Other syndromes with hair abnormalities may also show features of uncombable hair syndrome such as Rapp-Hodgkin ectodermal dysplasia syndrome, loose anagen syndromeLoose anagen syndrome
Loose anagen syndrome is primarily described in fair-haired children who have easily dislodgable hair....
, EEC syndrome (ectodermal dysplasia
Ectodermal dysplasia
Ectodermal dysplasia is not a single disorder, but a group of syndromes all deriving from abnormalities of the ectodermal structures. More than 150 different syndromes have been identified. Despite some of the syndromes having different genetic causes the symptoms are sometimes very similar...
, ectrodatyly and cleft lip/palate) and familial tricho-odonto-onychial ectodermal dysplasia with syndactyly
Syndactyly
Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, such as the siamang and kangaroo, but is an unusual condition in humans.-Classification:...
. However unlike these conditions, uncombable hair syndrome alone is not associated with physical, neurologic, or mental abnormalities.