A 2-month-old is diagnosed with spinal muscular atrophy via genetic testing, which reveals a homozygous deletion of SMN1. The parents inquire about a disease-modifying therapy that is administered orally on a daily basis. Which of the following treatments fits this description?
A 14-year-old boy presents with recurrent episodes of severe burning pain in his feet and lower legs, often precipitated by fever or physical activity. Examination is largely normal, but he has red-black skin lesions on his scrotum and around his umbilicus. This X-linked recessive disorder is caused by a deficiency in which enzyme?
An 8-month-old infant with hypotonia and ptosis is diagnosed with a congenital myasthenic syndrome. A trial of pyridostigmine leads to a noticeable worsening of his weakness. This paradoxical response strongly suggests a pathogenic variant in which of the following genes?
A 14-year-old undergoing chemotherapy develops a painful, predominantly sensory axonal neuropathy. His oncologist explains this is a dose-dependent side effect of one of his medications, which is known to also have a risk of optic neuropathy. Which of the following antibiotics is the most likely cause?
An 8-year-old boy presents with progressive bulbar palsy, sensorineural deafness, and facial weakness. Laboratory workup reveals an abnormal acylcarnitine profile. Targeted therapy with high-dose supplementation of which of the following could lead to clinical improvement?
A 10-year-old girl presents with a 3-month history of slowly progressive, symmetric proximal and distal weakness and paresthesias. Examination reveals areflexia. Cerebrospinal fluid analysis shows an elevated protein level with no pleocytosis. Which feature most helps to distinguish her condition from classic Guillain-Barré syndrome?
A 10-year-old girl with ptosis and generalized weakness is seronegative for anti-acetylcholine receptor antibodies. An antibody panel is sent to investigate other causes of autoimmune myasthenia gravis. Which antibody is associated with a form of myasthenia gravis that typically responds well to rituximab but may have a less favorable response to standard therapies?
A 6-month-old infant presents with recurrent, severe episodes of pain localized to the sacral region, often triggered by defecation. During these episodes, he exhibits erythema and tonic stiffening. This presentation of paroxysmal extreme pain disorder is caused by a pathogenic gain-of-function variant in which gene?
A 15-year-old with known myasthenia gravis is brought to the emergency department with a severe increase in weakness. She exhibits abdominal cramps, diarrhea, profuse sweating, and miosis. What is the most appropriate next step in management?
A 6-year-old boy with a known diagnosis of central core disease is scheduled for an orthopedic surgery requiring general anesthesia. The pediatrician is counseling the family and the anesthesiologist about potential risks. The use of which of the following anesthetic agents should be avoided in this patient?
