Mature-onset　diabetes　of　the　young　(MODY)　is　an　autosomal　dominant　genetic　disease　that　is　typically　diagnosed　during　childhood　or　early　adolescence.　The　primary　pathogenesis　of　MODY　involves　gene　mutations　that　impair　insulin　synthesis　and/or　secretion　by　islet　beta　cells,　rendering　the　condition　independent　of　insulin　resistance.　A　family　with　the　MODY-12　phenotype　caused　by　an　ATP-binding　cassette　subfamily　C　member　8　(ABCC8)　gene　mutation　was　investigated　in　the　present　study.　Clinical　data　were　collected　from　all　family　members,　and　second-generation　gene　sequencing　and　Sanger　sequencing　were　performed.　The　suspected　pathogenic　mutation　was　validated　by　Sanger　sequencing,　and　the　three-dimensional　structure　of　the　pathogenic　variant　protein　was　predicted　and　simulated　using　the　Swiss-Model　platform.　Five　individuals　with　MODY-12,　including　the　proband,　were　identified　in　this　family.　Second-generation　gene　sequencing　confirmed　that　all　family　members　carried　the　ABCC8　c.2500C＞T　(p.Arg834Cys)　mutation.　Structural　modeling　revealed　that　the　replacement　of　arginine　at　position　834　in　the　wild-type　protein　with　cysteine　results　in　the　formation　of　an　additional　hydrogen　bond　with　the　surrounding　amino　acids.　In　addition,　the　ABCC8　c.2500C＞T　carriers　in　this　family　experienced　recurrent　diabetic　ketoacidosis　and　acute　kidney　involvement　(AKI)　phenotypes,　and　all　patients　had　a　history　of　sodium-glucose　transporter　2　inhibitor　(SGLT2i)　use.　We　hypothesize　that　AKI　in　these　patients　may　be　pseudo-AKI　associated　with　the　use　of　SGLT2is.　However,　the　proband　exhibited　symptoms　indicative　of　rapidly　progressing　diabetic　nephropathy.　This　study　demonstrates　that　clinicians　managing　patients　with　MODY　should　be　aware　of　the　risk　of　acute　and　serious　complications,　particularly　as　SGLT2i　may　induce　pseudo-AKI,　which　could　ultimately　compromise　patients＇　long-term　renal　prognosis.