ESPE Abstracts

Background: Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy, characterized by unregulated insulin secretion. CHI is a challenging disease to diagnose and manage. Moreover, complicating the course of the disease with another metabolic disease like Maple syrup urine disease (MSUD) adds more challenges to the already complex management.

Case: We report a term male neonate with uneventful birth history. He developed symptomatic hypoglycemia with a blood glucose (BG) level of 1.9 mmol/l at 21 hours of life. A critical sample at that time showed high serum insulin level of 167.7 pmol/L, C-peptide >>1160 pmol/L and low ketones confirming the diagnosis of hyperinsulinism. Amino acid profile on dried blood spot by tandem mass spectrometry part of critical sample was done and showed high leucine and isoleucine levels indicating the diagnosis of MSUD. MSUD is then confirmed by HPLC which showed the presence of allo-isoleucine at 101 umol/L, and elevated levels of the three branched chain amino acids (leucine 724 (45.00–160.00), isoleucine 240 umol/L (28.00–95.00), and valine 390 umol/L (60.00–294.00). The diagnosis of CHI and MSUD was afterward confirmed by molecular genetic testing. The finding of a known pathogenic homozygous mutation in the ABCC8 gene (c.3748C>T, p.Arg1250*) confirmed CHI diagnosis. The presence of a homozygous mutation in the BCKDHA (c.1087, p.Arg363Trp) confirmed the MSUD diagnosis. The baby’s case is very challenging managing two rare autosomal recessive disorders. Managing his hypoglycemia with high glucose rate through intravenous fluids, frequent feeds with special MSUD formula, and medications for hyperinsulinism (Diazoxide and octereotide). Unfortunately his hyperinsulinism did not respond to all medical measures and he needed to go to a near total pancreatectomy. Through all his complicated course, he required very meticulous monitoring of his BG and amino acid profile (3 times/week on average) aiming to maintain the BG at 3.9 mmol and above and levels of the three branched chain amino acids at the disease therapeutic targets for a neonate.

Conclusion: This patient is perhaps the only known case of the occurrence of two rare life threatening disorders. Both hypoglycemia and Leucine encephalopathy can result in death or permanent neurological damage. This is complicated by the fact that both disorders have direct effect on the body metabolism of glucose and branched chain amino acids and there management in combination is very challenging. [DANA1] Need the reference values.