CDA and hyperinsulinemic hypoglycemia, familial, 4: We identified 6 different mutation signatures in our cohort: S1, spontaneous mutational processes associated with age; S3, associated with homologous repair deficiency (HRD); S2 and S13, associated with the activity of the APOBEC family of cytidine deaminases; and S6 and S15, associated with defective DNA mismatch repair (COSMIC v2, https://cancer.sanger.ac.uk/signatures/).