A 13-month-old boy is evaluated for failure to thrive and delayed physical and mental development. His mother reports that at 12 months he could barely lift his head and had difficulty sitting unsupported. The toddler has not started babbling or forming words. He is at the 10th percentile for height and 5th percentile for weight. Laboratory results show Megaloblastic anemia and normal ammonia level. Urine specimens reveal increase orotic acid . Supplementation with which of the following substances would most likely benefit this patient?

Question

A 13-month-old boy is evaluated for failure to thrive and delayed physical and mental development.  His mother reports that at 12 months he could barely lift his head and had difficulty sitting unsupported.  The toddler has not started babbling or forming words.  He is at the 10th percentile for height and 5th percentile for weight.  Laboratory results show Megaloblastic anemia and normal ammonia level. Urine specimens reveal increase orotic acid .  Supplementation with which of the following substances would most likely benefit this patient?

Quizplus · Accepted Answer

Eductional Objective: Orotic aciduria is a rare autosomal recessive disorder of de novo pyrimidine synthesis that occurs due to a defect in uridine 5'-monophosphate (UMP) synthase.  Children typically present with physical and mental retardation, megaloblastic anemia, and large amounts of urinary orotic acid.  Uridine supplementation can improve symptoms as uridine is converted to UMP via nucleoside kinases.

A 13-Month-Old Boy Is Evaluated for Failure to Thrive and Delayed