Genetic disorders Flashcards
What kind of mutation results in achondroplasia? What is the result of the mutation?
A point mutation that is a base substitution that results in a non conservative missense mutation. Results in an over active receptor and creates disturbances in bone growth
What kind of mutation results in Duchennes muscular dystrophy? What is the result of the mutation?
A point mutation that is an indel that results in a frameshift mutation that leads to a nonsense mutation that is a knockout mutation. Patients are unable to produce dystrophin and usually die by age 20
What kind of mutation results in cystic fibrosis?
A point mutation that is the deletion of a phenylalanine that results in a knockout mutation
Why does the deletion in cystic fibrosis not cause a frameshift?
It deletes 3 adjacent nucleotides, so the reading frame is unaffected
What kind of mutation results in Huntington’s disease? What is the result of that mutation?
An insertion mutation of a repeated region that expands the repeat. Results in a gain of function and an accumulation of toxic proteins
What kind of mutation results in Fragile X syndrome? What is the result of that mutation?
Insertion at a region with a repeated sequence that expands the repeat. Is a knockout mutation that causes the region on the chromosome to be full of repressor proteins instead of DNA as it is in the promotor region and stops RNA polymerase from binding
What diseases have defects in repair genes?
Cancer, immunodeficiency disorders, neurodegeneration, ataxia
What is mutated in Xeroderma pigmentosum? What is the result of that mutation?
The NER pathway. It knocks out the pathway, so patients are unable to repair pyrimidine dimers. They are extremely sensitive to sunlight
What is mutated in Cockayne syndrome? What is the result of that mutation?
The NER pathway, the mutation stops transcription coupled repair. Patients can’t repair pyrimidine dimers and are very sensitive to sunlight
