Review Question - QID 109132

An 18-year-old man presents to his primary care provider with his parents for a sports physical. He was last seen in the clinic several months ago when he was diagnosed with attention deficit hyperactivity disorder (ADHD). He was started on methylphenidate at that time and the patient now reports improvement in his ability to concentrate in school and at home. He hopes to play baseball in college and has begun lifting weights daily in preparation for baseball season. The patient has a healthy diet to fuel his exercise regimen. His parents have no concerns and are pleased with the recent improvement in his grades. His temperature is 98.6°F (37°C), blood pressure is 115/71 mmHg, pulse is 72/min, and respirations are 12/min. On physical exam, the patient has tall stature with average muscle mass for his age. He has no dysmorphic features. His chest has a normal appearance other than mild gynecomastia. The patient has sparse facial hair and a moderate amount of coarse pubic hair that extends across the pubis and spares the medial thighs. His testes are small and firm. Laboratory testing is performed and reveals the following:

Follicle-stimulating hormone (FSH): 42 mIU/mL
Luteinizing hormone (LH): 38 mIU/mL

Which of the following is the most likely etiology of this patient’s presentation?