A 34 year old woman seeks counseling because her father developed gait instability and choreiform movements in middle age. Genetic testing in the family identified a CAG trinucleotide repeat expansion. She asks why affected individuals in successive generations tend to develop symptoms at an earlier age. Which of the following terms best describes this phenomenon?
- A)Mosaicism
- B)Incomplete penetrance
- C)AnticipationGABARITO
- D)Loss of heterozygosity
- E)Variable expressivity
Explicação
This pattern is called anticipation. Expansion of unstable trinucleotide repeats during gametogenesis can lead to larger repeat numbers in later generations, producing earlier onset and more severe disease. Huntington disease and myotonic dystrophy are classic... Ver explicação completa e trilha adaptativa →