Hyperinsulinism-Hyperammonemia Syndrome


Hyperinsulinism-hyperammonemia syndrome (HHS; Glutamate dehydrogenase 1; GLUD1), an inherited condition, is caused by a defect in the GLUD1 gene which codes for mitochondrial glutamate dehydrogenase 1. It is a mitochondrial matrix enzyme, with a key role in the nitrogen and glutamate (Glu) metabolism and the energy homeostasis. An excessive activity of this enzyme results in high insulin and ammonia levels in blood; decrease level of glucose in blood. Symptoms and signs include shakiness, weakness, seizure, rapid pulse and confusion. Maintain normoglycemia is essencial to prevent neurologic damage. Some medications can be used to suppress insulin secretion.

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References

  1. Uniprot: P00367
  2. OMIM: Entry 606762
  3. De Lonlay P, Benelli C, Fouque F, Ganguly A, Aral B, Dionisi-Vici C, Touati G, Heinrichs C, Rabier D, Kamoun P, Robert JJ, Stanley C, Saudubray JM: Hyperinsulinism and hyperammonemia syndrome: report of twelve unrelated patients. Pediatr Res. 2001 Sep;50(3):353-7. Pubmed
  4. Glaser B, Thornton PS, Herold K, Stanley CA: Clinical and molecular heterogeneity of familial hyperinsulinism. J Pediatr. 1998 Dec;133(6):801-2. Pubmed
  5. MacMullen C, Fang J, Hsu BY, Kelly A, de Lonlay-Debeney P, Saudubray JM, Ganguly A, Smith TJ, Stanley CA: Hyperinsulinism/hyperammonemia syndrome in children with regulatory mutations in the inhibitory guanosine triphosphate-binding domain of glutamate dehydrogenase. J Clin Endocrinol Metab. 2001 Apr;86(4):1782-7. Pubmed
  6. Miki Y, Taki T, Ohura T, Kato H, Yanagisawa M, Hayashi Y: Novel missense mutations in the glutamate dehydrogenase gene in the congenital hyperinsulinism-hyperammonemia syndrome. J Pediatr. 2000 Jan;136(1):69-72. Pubmed