Introduction: Recently the incidence of type 2 diabetes was explosively increased in children and adolescents. The underlying mechanism of childhood-onset type 2 diabetes mellitus may be different to the adult-onset type 2 diabetes. Therefore, it is useful to conduct genetic study in children with type 2 feature to understand underlying cause of glycemic dysregulation as well as for the management of diabetes mellitus.
Case: A 25-month-old male was admitted at Urology department for the operation of scrotal mass and was referred to the department of Pediatrics because of hyperglycemia. Polydipsia and polyuria were reported from the parents. The child had no family history of diabetes mellitus. He was born at 36 weeks of gestation by normal vaginal delivery with birth weight of 2.61kg. Initial HbA1c level was 13.6%. Serum glucose, insulin, and C-peptide were 413 mg/dL, 2.0 uIU/mL, and 0.45 ng/mL, respectively. Under the impression of type 1 diabetes, subcutaneous insulin injection was started with NPH and regular insulin with total insulin dose of 0.5 U/kg/day. We increased insulin dose up to 0.75 U/kg/day at discharge. After discharge, autoantibodies were reported as negative. Glutamic acid decarboxylase antibody was less than 0.2 U/mL (Normal range: 0-1 U/mL) and anti-insulin antibody was 5% (Normal range: 0-7%). He was hospitalized once again with uncontrolled blood glucose level, and discharged after increasing dosage of insulin up to 1 U/kg/day. During follow-up at out-patient clinic, his HbA1c was maintained well, ranging from 6.3 to 6.9%. We gradually reduced insulin dose to 0.58 U/kg/day, but intermittent mild hypoglycemia was noticed. Under the suspicion of type 2 diabetes, we changed treatment modality from NPH and RI to Lantus and Sulfonylurea (GlimepirideTM). Furthermore, we discontinued Lantus and added MetforminTM. Blood glucose level was well controlled without severe hypoglycemia or hyperglycemia. With a strong suspicion of MODY, we performed targeted exome sequencing which included 29 genes associated with monogenic diabetes. Mutation of p.Asp209Glu in the gene ABCC8 was found. Both parents did not have any mutation in the region of ABCC8 gene.
Conclusion: It may be recommended to perform the genetic test to find the candidate gene of type 2 diabetes mellitus which developed in children and adolescents. Here we report a case with de novo mutation of ABCC8 gene in a child with MODY developed at 25 months of age.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology