COQ2 and hyperinsulinemic hypoglycemia, familial, 4: Pathogenic variants of the COQ2 gene and clinical manifestations, including neurologic and renal involvement, have previously been reported in the literature (Table 1).COQ2 deficiency has a variable presentation and can be associated with a severe multi organ system disorder [7–13], an intermediate nephrotic syndrome with or without neurological symptoms [9, 14–23], and milder later presentations of multi system atrophy and retinitis pigmentosa [24, 25].