A 42 year old man is evaluated for involuntary movements and personality change. His father died in his early 50s after progressive dementia. Examination shows choreiform movements and impaired saccadic eye movements. MRI demonstrates atrophy of the caudate nuclei with enlargement of the lateral ventricles. Which of the following best describes the genetic basis of this disorder?
- A)Paternal uniparental disomy of chromosome 15
- B)Autosomal recessive CTG trinucleotide repeat expansion
- C)Autosomal dominant CAG trinucleotide repeat expansion with anticipationGABARITO
- D)X linked mutation in dystrophin
- E)Mitochondrial mutation affecting oxidative phosphorylation
Explicação
Autosomal dominant CAG trinucleotide repeat expansion with anticipation is correct. Huntington disease is caused by expansion of CAG repeats in the HTT gene on chromosome 4, leading to toxic gain of function and degeneration of GABAergic neurons in the caudate... Ver explicação completa e trilha adaptativa →