A 4-year-old child presents with severe intellectual disability, minimal speech, frequent inappropriate laughter, seizures, and an ataxic gait. Genetic testing shows loss of maternal gene expression at chromosome 15q11–q13. The most likely diagnosis is?

A 2-month-old infant has a soft, nontender bulge at the umbilicus that protrudes when crying and is easily reducible. The infant is otherwise healthy. What is the most appropriate management?

Teenager with progressive ataxia, absent reflexes, loss of vibration sense, and hypertrophic cardiomyopathy. GAA repeat expansion on chromosome 9. The Cause is?

A newborn has severe hypotonia and poor feeding. At age 5, he develops hyperphagia and obesity. Genetic testing reveals a deletion on chromosome 15q11–q13 inherited from his father. What is the most likely diagnosis?

A 2-year-old boy presents with abdominal distension and a palpable right upper quadrant mass. Laboratory studies show markedly elevated alpha-fetoprotein (AFP). Imaging reveals a solitary liver mass. What is the most likely diagnosis?

A 2-year-old child presents with intermittent jaundice and abdominal pain. RUQ ultrasound shows dilation of the gallbladder and a fusiform dilation of the extrahepatic biliary tree that communicates with the bile ducts. What is the most likely diagnosis?

A premature neonate with jaundice is started on intravenous antibiotics for suspected sepsis. Shortly after receiving therapy, the infant develops worsening hyperbilirubinemia. Which of the following drugs is most likely responsible?

A full-term infant is exclusively breastfed. At what age should iron supplementation typically begin to prevent iron deficiency anemia?

HbAS on electrophoresis indicates:

A 2-year-old child who is not toilet trained needs a urine culture. What is the preferred method to collect a sterile urine sample?

A 14-year-old boy presents with sudden severe unilateral testicular pain. The testis is high-riding with an absent cremasteric reflex. What is the definitive treatment?

A 4-year-old child is diagnosed with Haemophilus influenzae type b (Hib) meningitis. Which of the following is indicated for close household contacts?

A 16-year-old presents with severe sore throat, muffled “hot potato” voice, trismus, and unilateral tonsillar swelling. What is the first-line management?

A 2-year-old child is brought to clinic because parents noticed a white reflex in photographs. Examination reveals leukocoria. Which of the following is the most important next step?

A 3-week-old neonate presents with fever, poor feeding, and lethargy. CSF shows elevated WBCs with neutrophilic predominance. What is the empiric antibiotic regimen for bacterial meningitis in this patient?

A 6-year-old presents with jaundice, splenomegaly, and anemia. Peripheral smear shows spherocytes. Labs reveal increased RDW. What is the most likely underlying mechanism?

A child with a history of poliomyelitis develops a waddling gait. When standing on the right leg, the left hip drops. Which nerve is most likely damaged?