A 2-year-old, known for self-injurious behavior and intermittent ataxia, has sustained moderate increase in plasma tyrosine and urinary 4-hydroxyphenylpyruvic acid. Which additional test would best confirm the most likely diagnosis?
A 16-year-old female presents with periodic muscle weakness, anxiety, and constipation. She has a history of recurrent abdominal pain. She takes oral contraceptives containing progestin. Which of the following best explains her recurrent symptoms?
A 10-day-old infant presents with lethargy, poor feeding, and a musty odor. Newborn screening reveals elevated plasma phenylalanine. What is the next best step in management?
A neonate has a positive newborn screen for elevated methionine. Which associated complication should be most carefully monitored in classic homocystinuria?
An infant presents in the first week of life with vomiting, hypotonia, and a “maple syrup” odor to the urine. What plasma amino acid is expected to be most elevated?
A 2-month-old with poor feeding, convulsions, and a “cat urine” odor is found to have metabolic acidosis and ketosis, responsive to high-dose biotin. Which deficiency is most likely?
A breastfed newborn has photosensitive dermatitis and intermittent ataxia, with increased urinary indican. What is the most effective treatment?
A previously healthy 4-year-old presents to the emergency department after an episode of vomiting and lethargy triggered by a viral infection. Laboratory findings reveal severe hypoglycemia and absent ketones. Which disorder is most likely?
A 2-year-old is hospitalized with altered mental status, hypoglycemia, and hepatomegaly after vomiting for 12 hours. Plasma free carnitine is low. What is the first dietary intervention?
A 2-week-old infant presents with vomiting, jaundice, hepatomegaly, and reducing substances in the urine after feeding. Which diagnosis is most likely?