For one patient with features of metabolic acidosis, recurrent hypoglycemia, poor‐feeding, and vomiting, the initial panel test did not identify any mutations, while a positive diagnosis by WES was received as a Combined oxidative phosphorylation deficiency‐23(COXPD23, OMIM 616198) (Kopajtich et al., 2014), one of the common causes of inborn errors in energy metabolism. The gene discussed is GTPBP3; the disease is metabolic acidosis.