CARS1

Cysteinyl-tRNA synthetase 1 is an enzyme that in humans is encoded by the CARS1 gene. It is an aminoacyl [tRNA synthetase] that attaches the cysteine amino acid onto its corresponding transfer RNA. Cysteinyl tRNA in turn is used by the ribosome to transfer cysteine onto a growing peptide chain during protein synthesis, according to the genetic code.

Clinical significance

Bi-allelic mutations in CARS1 have been identified to cause the non-photosensitive form of trichothiodystrophy. This disorder is characterized by neurodevelopmental problems, sulfur-deficient brittle hair and nails, ichthyosis, and growth retardation. In contrast to the photosensitive version of TTD, which has the characteristics of progressive neuropathy and accelerated aging, NPS-TTD is not linked with premature aging.
According to one study, individuals who present with bi-allelic CARS loss-of-function mutations are unique in presenting with a brittle-hair-and-nail phenotype, which could be related to the high cysteine content in human keratins.