Premium
Amino‐acid composition in trichorrhexis nodosa
Author(s) -
RUSHTON D.H.,
NORRIS M.J.,
JAMES K.C.
Publication year - 1990
Publication title -
clinical and experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 78
eISSN - 1365-2230
pISSN - 0307-6938
DOI - 10.1111/j.1365-2230.1990.tb02013.x
Subject(s) - dermatology , composition (language) , medicine , art , literature
Summary Trichorrhexis nodosa is a common shaft defect affecting scalp hair. Two‐hundred scalp hairs exhibiting trichorrhexis nodosa were obtained from two normal females; samples were prepared from proximal shaft, pre‐nodule, nodule and post‐nodule sections and analysed for their respective amino‐acid compositions. Significant reductions in cystine ( P < 0.001) of the pre‐nodule, nodule and post‐nodule sections, which decreased by 17.2%, 19.8% and 14.3%, respectively, and an increase in the acidic amino acids ( P < 0.03) were found, compared to values obtained from proximal shaft of the same hairs. The majority of nodules occurred within the last 10% of the shaft, and the similarity in amino‐acid compositions between pre‐nodule, nodule and post‐nodule sections suggests that ‘weathering’ is the major factor influencing nodule occurrence. It is postulated that nodule formation requires a specific degree of exposure to ‘weathering’ together with a reduction in cuticle cell coverage. It is suggested that an initial structural detect, created by a change in the DNA coding for a cuticle polypeptide fraction, could be responsible for the selective and isolated presentation of the nodule within a ‘weathered’ section of hair shaft.