Trichothiodystrophy is a human inherited disorder characterized by premature agi
ID: 80461 • Letter: T
Question
Trichothiodystrophy is a human inherited disorder characterized by premature aging, including osteoporosis, osteosclerosis, early graying, infertility, and reduced life span. The results of studies showed that the mutation that causes this disorder occurs in a gene that encodes a DNA helicase. What is the MOST likely explanation as to why a defect involving a DNA helicase causes premature aging? It likely would enhance DNA replication so that tissues age more quickly. It might reduce the level of nonhomologous end joining repair so that cells would not be able to repair their DNA in the G2 stage of the cell cycle. It might enhance the level of spontaneous mutagenesis because cells would not be able to remove oxidized guanines from their genomes, and this would lead to cell death and accelerated aging. It might reduce the level of nucleotide-excision repair in many tissue types, which would lead to cell death and accelerated aging. It might increase the level of spontaneous mutations because it would increase depurinations in the DNA, and this would lead to cell death and accelerated aging.Explanation / Answer
Ans:
Trichothiodystrophy is a human inherited disorder characterized by premature aging, including osteoporosis, osteosclerosis, early graying, infertility, and reduced life span, The result of studies showed that the mutation that causes this disorder occurs in a gene that encodes a DNA helicase. The most likely explanation as to why a defect involving a DNA helicase causes premature aging is: It might reduce the level of nucleotide-excision repair in many tissue types, which would lead to cell death and accelerated aging.
Explanation:
- Trichothiodystropy, also known as TTD, is a rare inherited genetic disorder characterized by hair that is defecient in sulfur, an element that is normally responsible for providing strength to hair.
- Nucleotide excision repair (NER) is one such DNA repair pathway that detects and removes several type of DNA lesions, and defects in NER have been linked to rare autosomal recessive diseases including trichothiodystrophy (TTD).
- Thus, trichothiodystrophy is NER deficient photosensitive disorder.
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