Objective: To study the etiology, clinical presentation and outcome of infantile onset diabetes mellitus (IODM).
Design: Descriptive cohort study. Retrospective study from 1999-2007 and prospective from 2008-2012.
Setting: The diabetic clinic at a Pediatric tertiary care referral institute in Chennai.
Methods: All infants diagnosed to have diabetes at less than one year of age were studied. Study variables were age at onset, gender, mode of presentation, birth weight, initial blood glucose, serum HbA1c, serum c peptide levels, outcome at initial presentation, insulin requirement, associated comorbid conditions, genetic analysis and outcome at the end of the study or until they were followed up.
Results: 40 infants with infantile onset diabetes were studied, constituting 8% of all children with onset of DM at less than 12 years of age. 67.5% of these children presented with diabetic keto acidosis (DKA), only 30% had a provisional diagnosis of DM or DKA at first physician contact. 63% of IODM with onset less than 6 months and 30% with onset more than 6 months were of low birth weight. Nearly 85% of the study group had low C-peptide levels. 84.5% of IODM with onset less than 6 months and 55% of those with onset more than 6 months were monogenic. Wolcott Rallison syndrome was the commonest type encountered. Genetic diagnosis aided switching over from insulin to oral sulphonylurea in 5 children with KCNJ11 and ABCC8 mutations. Missed diagnosis, recurrent admissions for metabolic instability and developmental delay were common problems in IODM. Mortality at 12.5 year follow up was 32.5%.
Conclusions: IODM with onset at less than 6 months is predominantly monogenic and low birth weight is more common. 55% of IODM were misdiagnosed at onset. Developmental delay is the common co morbid condition in IODM. Genetic diagnosis aids change of therapy to oral sulphonylurea.