Endocrine Abstracts

Introduction: Neonatal diabetes mellitus is a rare form of diabetes, diagnosed within the first six months of life. We report a case of a 24-year-old patient with permanent neonatal diabetes.

Case Report: The patient had no relevant family history. Her mother had no gestational diabetes. Personal history included: Normal birth weight, polycystic ovarian syndrome and ovarian teratomas. She was diagnosed of diabetes at 3 months of age, starting immediately with insulin treatment. Glucose control had always been optimal (HbA1c l <6.7%). Acute diabetic complications included: symptomatic hypoglycemias every 3 days, usually after dinner and, less frequently nighttime hypoglycemias. No hyperglycemias that required in hospital management. No chronic metabolic complications. The patient came to our clinic to continue follow up. We completed her work up doing islet antibodies detection (anti GAD65, anti tyrosine phosphatase IA2, anti insulin and anti zinc transporter), and as expected the results were negative. Considering the age of the diagnosis, genetic testing for monogenic forms of diabetes was performed, discovering a heterozygous mutation c.323Ag (pY108C) in INS gene. Family genetic mutation are still pending.

Discussion: Neonatal diabetes mellitus have an incidence of 1 in 500000 live births. Most common genes are KLF 11, ABCC8 and less frequently INS gene (30%, 19% and 14% respectively). Depending on the severity of the mutations insulin bioactivity will be affected, ranging from a decreased biosynthesis to altered transcription. Clinical implications include transient requirement of insulin, later switching to sulfonylureas or even completely stopping hypoglycemic treatment; and permanent insulin treatment. In the latter, the risk of ketoacidosis also depends and the recessive or dominant inheritance.

Conclusions: Monogenic forms of diabetes are uncommon, however it is important to consider them in the differential diagnosis of particular cases. Genetic mutation study is important to assess future treatment options and the risk of ketoacidosis.