Complex IV

A child was born at term after an unremarkable pregnancy. There were some feeding difficulties after birth, and he was noted to be quite sleepy. His initial newborn screening was suggestive of glutaric aciduria type 1; however, urine organic acids done on day 6 of life showed no elevation of glutaric acid, with a trivial elevation of 3-hydroxyglutaric acid. He was seen in the metabolic clinic on that day as a follow-up to the positive NBS and was difficult to arouse and was hypotonic. Stat blood gases were done and showed a pH of 7.18, PO2 of 51mm Hg, CO2 of 48mm Hg, bicarbonate of 17mmol/L, a base deficit of 11, and a lactate concentration of 12.8mmol/L (N<2.2mmol/L). Consequently, he was admitted to the pediatric intensive care unit (PICU). In the PICU, he was given intravenous fluids and started on nasogastric feeds. His lactate remained very high for 2weeks (range=5.4>15.6mmol/L), and he had a percutaneous muscle biopsy taken from the vastus lateralis, and a skin biopsy was also taken for fibroblast analysis (see below).