MPLKIP
M-phase-specific PLK1-interacting protein is a protein that in humans is encoded by the MPLKIP gene. Patients with an inherited defect in both alleles of the gene suffer from trichothiodystrophy, 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 Cys content of the hairs. Only a minority of the TTD cases carry a MPLKIP defect: more frequently, the gene ERCC2 is mutated, which encodes a subunit of the protein complex TFIIH that is required for general transcription and for nucleotide excision repair of DNA damage.