C7orf11

TTD non-photosensitive 1 protein is a is_associated_with::protein that in humans is encoded by the C7orf11 is_associated_with::gene. . Patients with an inherited defect in both alleles of the gene suffer from is_associated_with::trichothiodystrophy (TTD), a disease hallmarked by brittle hair and nails and usually by developmental difficulties as well. One patient carries a homozygous deletion of the whole gene area, which indicates that the gene is not essential for embryonic development. TTD can be diagnosed by the presence of tigertail-striped patterns in hair visible under polarised light microscopy, or biochemically by a reduced cystein content of the hairs. Only a minority of the TTD cases carry a TTDN1 defect: more frequently, the gene is_associated_with::ERCC2 is mutated, which encodes a subunit of the protein complex is_associated_with::TFIIH that is required for general transcription and for is_associated_with::nucleotide excision repair of DNA damage.