A 4-year-old child, asymptomatic until a viral illness, develops hepatomegaly, hypoglycemia with hyperlactatemia, and increased uric acid. His labs show hyperlipidemia. What major complication should be monitored?
A 2-year-old with intermittent vomiting and episodes of metabolic acidosis is found to have elevated isovalerylglycine in urine. What therapy can help excrete the toxic metabolite?
A toddler presents with frequent upper respiratory infections, skeletal dysplasia, delayed speech, and inguinal hernias. Labs reveal mixed glycosaminoglycanuria. Which of the following is a risk and affects long-term prognosis?
A 7-month-old presents with vomiting, failure to thrive, and abnormal liver tests. He is found to have reducing substances in urine and bilateral cataracts. What is a potential complication of delayed diagnosis?
A school-aged child with spastic diplegia, scissoring of lower limbs and gradual loss of milestones is found to have extremely high plasma arginine. What is the primary recommended dietary change?
A full-term 1-day-old neonate develops severe hypoglycemia with poor feeding and hypotonia within the first 48 hours of life. Labs show low beta-hydroxybutyrate and free fatty acids. Which is the most likely pathophysiological mechanism?
A 14-month-old girl presents with coarse facial features, corneal clouding, hepatosplenomegaly, and joint contractures, but normal cognitive development. Enzyme testing reveals markedly deficient arylsulfatase B activity, and urine glycosaminoglycans show elevated dermatan sulfate without elevation of heparan sulfate. What is the most likely diagnosis?
A 6-month-old has macrocephaly, subdural hematomas, and dystonia. Urine organic acids show increased glutaric acid. What is the enzyme defect?
A 10-year-old boy complains of sun-induced burning pain and swelling of the dorsal hands. Physical exam reveals some linear erosions, but no blistering. Erythrocyte protoporphyrin is markedly increased and mostly not complexed with zinc. What is the best confirmatory next step?
A previously healthy infant develops megaloblastic anemia unresponsive to vitamin B12 and folate, along with failure to thrive and mild developmental delay. Urine organic acid analysis reveals markedly elevated orotic acid, and microscopic examination shows orotic acid crystals in the urine. Which defect in purine/pyrimidine metabolism best explains these findings?