A 6-month-old baby has been feeding poorly and has been leth

A 6-month-old baby is brought to the pediatrician because she has been feeding poorly and has been lethargic for the past several months. The baby has also started breathing more rapidly than normal and recently had a seizure. Laboratory studies reveal a serum pH of 7.20, an anion gap of 19, elevated levels of pyruvate and alanine, and decreased levels of citrate.

What is the most likely diagnosis?

Citrate levels are low because pyruvate is being diverted from conversion to citrate and instead is being converted to OAA via pyruvate carboxylase. OAA is part of the TCA cycle but the conversion to malate is reversible. therefore it is converted to malate, shunted out of the mito and used in gluconeogenesis. Meanwhile since glycolysis is the means of producing energy here, proteins will break down to contribute to gluconeogenesis so Alanine will be increased.