Other relevant examples include a patient with global developmental delay and regression, failure to thrive, lactic acidosis, rigidity, and seizures, in whom GS detected a homozygous deep intronic variant in COQ2 (NM_015697.7:c.403+355 C > G), the variant is extremely rare (not found in gnomAD) and detected for the first time on our laboratory. The gene discussed is COQ2; the disease is lactic acidosis.