A case of congenital hyperinsulinemia (CHI) involved two mutations in the ABCC8 gene, namely, c.2921-9 G>A (chr11:17428685) and c.3022_3028delGGCATC (chr11:17428568), demonstrating successful outcomes with tailored treatment guided by genetic testing. The gene discussed is ABCC8; the disease is congenital isolated hyperinsulinism.