Identification of C7orf11 (TTDN1) Gene Mutations and Genetic Heterogeneity in Nonphotosensitive Trichothiodystrophy

Program in Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, ON, Canada.
The American Journal of Human Genetics (Impact Factor: 10.93). 04/2005; 76(3):510-6. DOI: 10.1086/428141
Source: PubMed


We have identified C7orf11, which localizes to the nucleus and is expressed in fetal hair follicles, as the first disease gene for nonphotosensitive trichothiodystrophy (TTD). C7orf11 maps to chromosome 7p14, and the disease locus has been designated "TTDN1" (TTD nonphotosensitive 1). Mutations were found in patients with Amish brittle-hair syndrome and in other nonphotosensititive TTD cases with mental retardation and decreased fertility but not in patients with Sabinas syndrome or Pollitt syndrome. Therefore, genetic heterogeneity in nonphotosensitive TTD is a feature similar to that observed in photosensitive TTD, which is caused by mutations in transcription factor II H (TFIIH) subunit genes. Comparative immunofluorescence analysis, however, suggests that C7orf11 does not influence TFIIH directly. Given the absence of cutaneous photosensitivity in the patients with C7orf11 mutations, together with the protein's nuclear localization, C7orf11 may be involved in transcription but not DNA repair.

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Available from: Jacques S Beckmann
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    • "Mutations in the TTDN1 gene are associated with the nonphotosensitive form of TTD [13] [14]. However, the majority of non-photosensitive TTD patients (approximately 80%) has not yet been linked with any causative gene. "
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