SAT-664 Fluctuating Blood Glucose in an Infant with Newly Diagnosed IPEX Syndrome

Abstract

Background: In the IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked) syndrome, Type 1 diabetes mellitus is the most common endocrine complication and usually occurs with a variable presentation from immediately at birth to within the first few months of life. Clinical case: A four-month-old male presented for evaluation of failure to thrive, eczema, and diarrhea. In the ED, his glucose value was 246 mg/dL with beta-hydroxybutyrate of 0.29 mmol/L (0.00-0.30). Within eight hours and without insulin, he became hypoglycemic and required dextrose-containing fluids to maintain euglycemia; he was quickly made NPO and started on TPN due to excessive stool output. For nearly two weeks he required no insulin while receiving 84g of dextrose per day (21 g/kg/day) in TPN. He developed bloody stools on the day that he started receiving Tacrolimus and IVIG and required transfer to the ICU, and an insulin need of 1 unit/kg/day developed with this worsening of his systemic illness. After the bloody stools resolved, immunosuppression with Rituximab was initiated. Once bowel function improved, Pedialyte and formula were slowly reintroduced and for three weeks his insulin requirement varied from 0.2-0.4 units/kg/day. In his seventh week of hospitalization his insulin was discontinued due to hypoglycemia, and at the time of discharge he had been without insulin for ten days on ad lib formula feeding. Hemoglobin A1c on admission was 10.2%, and repeat was 10.3%. A fructosamine level was obtained to evaluate the discrepancy between the initial HgbA1c and being euglycemic. It was 269 umol/L (190-270), equivalent to an approximate HgbA1c of 6.5%, suggesting that hyperglycemia resulting in an elevated HgbA1c occurred early in his life and had improved in the days to weeks prior to admission. Further testing revealed an elevated GAD-65 antibody of >250 IU/mL (<5) but normal ICA 512 and insulin autoantibody. His clinical picture was consistent with IPEX syndrome, confirmed with rapid whole genome sequencing showed a pathogenic hemizygous c.1010G>A p.Arg337Gln variant in the FOXP3 gene. A HgbA1c performed prior to discharge, eight weeks after the initial, was 6.6%. This spontaneous resolution of hyperglycemia in IPEX, with insulin needs developing only when he had worsening systemic illness as demonstrated by bloody stools, has yet to be described. Conclusion: Hyperglycemia fluctuated in the first few months of life in a patient with IPEX syndrome, likely related to severity of systemic illness and control of enteropathy.