A 1-year-old boy is brought to the clinic by his mother due to recurrent upper respiratory tract infections and oral fungal infections. Physical examination reveals low set ears and fish-like mouth. Laboratory tests reveal hypocalcemia and chest x-ray shows no thymus shadow.
What is the most likely etiology of hypocalcemia in this case?
A-Decreased secretion of parathyroid hormone
B-End-organ hyposensitivity to parathyroid hormone
C-End-organ hyposensitivity to calcitonin
D-Increased secretion of calcitonin
E-Increased secretion of parathyroid hormone
This case is most likely Di George syndrome. It is characterized by a defect in the third pharyngeal pouch which gives rise to inferior parathyroid and thymus. The fourth pharyngeal pouch gives rise to superior parathyroid.
The correct answer is A