A 16-year-old boy presents with slowly progressive proximal muscle weakness over 3 years but remains ambulatory and plays modified sports. His maternal uncle had a similar disorder and survived into adulthood. Vital signs are normal (BP 120/78, HR 88, RR 16, Temp 37°C). Serum creatine kinase is elevated at 2,200 IU/L. Cardiac evaluation shows no involvement. Which of the following mutations is most likely present?
- A)Mitochondrial DNA deletion impairing oxidative phosphorylation
- B)In frame mutation in the dystrophin gene allowing partially functional proteinGABARITO
- C)Nonsense mutation in the SMN1 gene
- D)Paternal CAG repeat expansion in the androgen receptor gene
- E)Postsynaptic acetylcholine receptor mutation
Explicação
In frame mutation in the dystrophin gene allowing partially functional protein is correct. Becker muscular dystrophy is a milder X linked allelic variant of Duchenne in which dystrophin is decreased or abnormal but not absent. The later onset and slower progre... Ver explicação completa e trilha adaptativa →