Progression of diabetic retinopathy during pregnancy in a woman with ABCC8-MODY.

Summary: Activating mutations in the ABCC8 gene are extremely rare and cause ABCC8-MODY. The phenotype is variable with onset of diabetes in childhood/early adulthood. Retinopathy is the most common reported complication. We describe a 31-year-old primigravida woman referred to and seen at our antenatal ambulatory diabetes clinic at 6 weeks plus 5 days gestation. She had a strong family history of diabetes and was diagnosed at the age of 11 years. Genetic testing revealed an activating pathogenic c.4139G>A variant in the ABCC8 gene. She was managed with glibenclamide, sitagliptin, and dapagliflozin. Her complications included mild bilateral non-proliferative retinopathy and necrobiosis lipoidica. Her BMI was 19 kg/m2, and HbA1c was 68 mmol/mol. Oral agents were discontinued, and insulin therapy was commenced. At 22 weeks gestation, routine retinal screening identified progression to bilateral active proliferative diabetic retinopathy (time in range for pregnancy (TIRp) 68%, HbA1c 39 mmol/mol). She received four sessions of panretinal photocoagulation (PRP) bilaterally between 22 and 33 weeks gestation. There was no associated loss of vision or nephropathy. TIRp was ≥70% for the remainder of the pregnancy. She delivered a 3.9 kg unaffected female infant at 38 weeks via elective caesarean section without maternal or neonatal complications. Bilateral active proliferative retinopathy persisted up to 61 weeks postnatally and required additional PRP. Forty-six weeks post-partum, after ceasing breastfeeding, insulin was switched to glibenclamide and dapagliflozin. This is the first case report of rapid progression of clinically significant diabetic retinopathy during pregnancy in a woman with ABCC8-MODY. This is an unusual finding as there is a relatively low risk of significant progression of diabetic retinopathy in women with type 2 diabetes during pregnancy. Learning points: Rapid progression of diabetic retinopathy during pregnancy is an uncommon complication in women with type 2 diabetes. This woman with ABCC8-MODY developed rapidly progressive clinically significant diabetic retinopathy without nephropathy during pregnancy. There is a paucity of literature regarding pregnancy-related complications of ABCC8-MODY. This case highlights the risks of end organ disease in a rare form of diabetes.