A 3-year-old boy presents with hyperphagia, rapid weight gain despite normal appetite regulation attempts, hypotonia, and small hands and feet. He has moderate developmental delay and no history of feeding difficulties in infancy. Vital signs show BP 95/60, HR 88, RR 22, Temp 37°C, SpO2 98%. Growth hormone and thyroid function tests are normal. Genetic testing reveals a deletion on chromosome 15 inherited from his father. Which mechanism best explains this disease presentation?
- A)Balanced reciprocal translocation
- B)Expansion of CGG trinucleotide repeats with methylation
- C)Defect in maternally inherited mitochondrial DNA
- D)Defect in paternally expressed genes due to genomic imprintingGABARITO
- E)Mutation in a DNA mismatch repair gene
Explicação
Prader Willi syndrome results from loss of paternally expressed genes on chromosome 15, typically due to paternal deletion or maternal uniparental disomy. Genomic imprinting means one parental copy is epigenetically silenced, so loss of the active paternal all... Ver explicação completa e trilha adaptativa →