Objectives

Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes, diagnosed before age 6 months. We aimed to describe the clinical characteristics, molecular genetics, and long-term follow-up of NDM patients from a single pediatric endocrine center in Israel.

Methods

Retrospective study (1975-2020) of all patients diagnosed with diabetes before 6 months of age, who tested negative for pancreatic autoantibodies. Medical records were reviewed for demographic, familial and medical history, and clinical and biochemical features; a genetic analysis was performed.

Results

Of 24 patients, nine had transient neonatal diabetes (TNDM) and 15 permanent neonatal diabetes (PNDM), of whom five had rare syndromic causes. Genetic etiology was revealed in 87.5% of the NDM cohort, and the most common causes were ABCC8 mutations in TNDM and KCNJ11 and insulin gene mutations in PNDM.

The switch from insulin to off-label sulfonylurea therapy was successful for 5/9 (56%) of the qualifying candidates. Severe hypoglycemia and diabetic ketoacidosis developed in 2 (8%) patients, and chronic diabetes complications in 5 (21%) patients with more than ten years NDM.

At last follow-up, weight and height of all but two syndromic PNDM patients were normal. The median height-SDS of the TNDM subgroup was significantly taller and the mean weight-SDS significantly heavier than those of the PNDM subgroup (-0.52 (-0.67, -0.09) vs. -0.9 (-1.42, -0.3) (P=0.035) and 0.22±0.69 vs. -0.89±1.21 (P=0.02), respectively). PNDM patients showed no incremental change in mean weight SDS over the time.

Conclusion

The Israeli NDM cohort has clinical and genetic characteristics comparable with other populations. Patients with TNDM were taller and heavier than those diagnosed with PNDM, although both show rapid catch-up growth and reached normal growth parameters. Chronic diabetes complications developed in patients with long-standing NDM.

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