A 5-year-old boy is brought to clinic by his parents for evaluation of developmental concerns. He was born with severe micrognathia and glossoptosis, which necessitated emergency tracheostomy on the first day of life to relieve upper airway obstruction. Physical examination reveals a small, receding mandible, a U-shaped cleft palate, and bilateral knee and elbow contractures. Imaging confirms mandibular hypoplasia. The combination of these findings is consistent with Robin sequence. Which of the following best describes the primary embryologic mechanism underlying this condition?
- A)Failure of neural crest cell migration into the first pharyngeal arch during weeks 4-6 of gestation
- B)Insufficient growth and elongation of the mandibular process during the first trimesterGABARITO
- C)Abnormal fusion of the palatal shelves with the vomer and nasal septum
- D)Failure of Meckel cartilage to serve as a template for mandibular bone formation
- E)Premature differentiation of maxillary process tissue, preventing mandibular expansion
Explicação
Robin sequence is characterized by a primary defect of mandibular hypoplasia (micrognathia) occurring during the first trimester, which secondarily causes glossoptosis and airway obstruction. The tongue falls back into the pharynx, and this mechanical obstruct... Ver explicação completa e trilha adaptativa →