An infant with hypercalcemia and hyperammonia: inborn error of metabolism or not? Answers

Excerpt

Pathological findings of this patient were mild dehydration, oral intolerance, and metabolic acidosis with alkaline urine and normal anion gap, hyperammonia, hypercalcemia, hypokalemia, positive urine anion gap, nephrolithiasis, and hypercalciuria. These findings were consistent with a diagnosis of distal renal tubular acidosis (dRTA). Intravenous fluid supply and oral sodium bicarbonate replacement therapy at 2 mEq/kg/day improved the metabolic acidosis, hyperammonemia, and dehydration in a few days. Potassium citrate was added for hypokalemia and prevention of urinary calculi. The serum ammonia level reduced to 97 mg/dL on the seventh day of treatment and the patient was discharged after an 18-day hospitalization. Ultimately, whole exome sequencing demonstrated a novel homozygote mutation in ATP6VOA4 gene, c.474delGinsTC (p.E158Dfs*29) (p.Glu158Asp*29). Our patient had weight gain with medication. …