How to cite this article: Morice-Picard F, Cario-André M, Rezvani H, Lacombe D, Sarasin A, Taïeb A. 2009. New clinico-genetic classification of trichothiodystrophy. Am J Med Genet Part A 149A:2020–2030.
New clinico-genetic classification of trichothiodystrophy†
Article first published online: 13 AUG 2009
Copyright © 2009 Wiley-Liss, Inc.
American Journal of Medical Genetics Part A
Special Issue: Ankyloblepharon-Ectodermal Defects-Cleft Lip and/or Palate Syndrome and Ectodermal Dysplasias
Volume 149A, Issue 9, pages 2020–2030, September 2009
How to Cite
Morice-Picard, F., Cario-André, M., Rezvani, H., Lacombe, D., Sarasin, A. and Taïeb, A. (2009), New clinico-genetic classification of trichothiodystrophy. Am. J. Med. Genet., 149A: 2020–2030. doi: 10.1002/ajmg.a.32902
- Issue published online: 20 AUG 2009
- Article first published online: 13 AUG 2009
- Manuscript Accepted: 4 APR 2009
- Manuscript Received: 11 FEB 2009
- DNA repair;
- transcription factor THFIIH;
Trichothiodystrophy (TTD) is a congenital hair dysplasia with autosomal recessive transmission. Cross banding pattern under polarized light plus trichoschisis and a low sulfur content of hair shafts define the disorder, which is associated with variable and neuroectodermal symptoms. So-called photosensitive forms of TTD (with low level of in vitro UV-induced DNA repair, not constantly associated with marked clinical photosensitivity) are caused by mutations in genes encoding subunits of the transcription/repair factor IIH (TFIIH). Ten percentage of nonphotosensitive patients are known to have TTDN1 mutations, the specific role of which is unknown. We studied nine patients recruited at our institution and reviewed 79 with molecular analysis out of 122 TTD patients reported in literature with the aim to collect systematically the clinical findings in TTD patients and establish genotype–phenotype correlations. The frequency of congenital ichthyosis, collodion-baby type, was significantly higher in the TFIIH mutated group. Hypogonadism was significantly more frequent in the non-photosensitive group. There was no statistical difference regarding osseous anomalies. Mutations in TFIIH sub-units leading to abnormal expression in genes involved in epidermal differentiation could explain the particular dermatological changes seen in photosensitive cases of TTD. We suggest a new clinico-genetic classification of TTD, which may help clinicians confused by the current acronyms used (IBIDS, PIBIDS…). Understanding the TTD ichthyotic phenotype could lead to therapeutic advances in the management of TTD and other types of ichthyoses. © 2009 Wiley-Liss, Inc.