A 10-year-old girl presents with progressive muscle weakness and difficulty walking. Her parents note that she has always been "clumsy" and had delayed motor milestones. On examination, you notice foot deformities and absent deep tendon reflexes. What might be the diagnosis and what are the next steps?
This patient's presentation of progressive muscle weakness, difficulty walking, and foot deformities, in conjunction with absent deep tendon reflexes, is suggestive of Charcot-Marie-Tooth disease, a group of inherited disorders that affect peripheral nerves. The next steps would involve electromyography (EMG) to detect abnormal electrical activity in the muscles and nerve conduction velocity (NCV) test to see how fast the nerves transmit signals. Genetic testing can help identify the specific type of Charcot-Marie-Tooth disease, which can guide management and counseling on prognosis.