Trichothiodystrophy: an electron-histochemical study of the hair shaft.

We have used sensitive electron-histochemical methods to study the subtle ultrastructural variations of cystine incorporation into the hair shaft in trichothiodystrophy. We have shown a general reduction in the cystine (sulphur) content of both the cuticle and the cortex. Discontinuity, and in some cases, complete absence of the cuticular A-layer results in premature weathering of the cuticle and weakening of the hair shaft. The ultrastructural findings support the work of Gillespie & Marshall (1981) in demonstrating the absence or re-characterization of the high sulphur matrix proteins and show further evidence for the incorporation, and abnormal distribution and deposition of sulphur-rich proteins in the hair cortex and cuticle. We conclude that the similar yet different results obtained from each patient's hair sample are characteristic of trichothiodystrophy, a neuro-ectodermal symptom complex which may represent a final common pathway of more than one metabolic disturbance.