European Journal of Endocrinology (2009) 161 731–735 ISSN 0804-4643 CLINICAL STUDY Hyperinsulinism–hyperammonaemia syndrome: novel mutations in the GLUD1 gene and genotype–phenotype correlations Ritika R Kapoor, Sarah E Flanagan1, Piers Fulton1, Anupam Chakrapani2, Bernadette Chadefaux3, Tawfeg Ben-Omran4, Indraneel Banerjee5, Julian P Shield6, Sian Ellard1 and Khalid Hussain Developmental Endocrinology Research Group, Molecular Genetics Unit, London Centre for Paediatric Endocrinology and Metabolism, Great Ormond Street Hospital for Children NHS Trust, and The Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK, 1Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter EX2 5DW, UK, 2Department of Inherited Metabolic Disorders, Birmingham Children’s Hospital, Birmingham B4 6NH, UK, 3Metabolic Biochemistry, Hoˆpital Necker – Enfants Malades, Universite´ Paris Descartes, Paris, France, 4Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation and Weil-Cornell Medical College, Doha, Qatar, 5Department of Paediatric Endocrinology, Royal Manchester Children’s Hospital and Alder Hey Children’s Hospital, Manchester M27 4HA, UK and 6Department of Child Health, Bristol Royal Hospital for Children, Bristol BS2 8BJ, UK (Correspondence should be addressed to K Hussain; Email:
[email protected]) Abstract Background: Activating mutations in the GLUD1 gene (which encodes for the intra-mitochondrial enzyme glutamate dehydrogenase, GDH) cause the hyperinsulinism–hyperammonaemia (HI/HA) syndrome. Patients present with HA and leucine-sensitive hypoglycaemia. GDH is regulated by another intra-mitochondrial enzyme sirtuin 4 (SIRT4). Sirt4 knockout mice demonstrate activation of GDH with increased amino acid-stimulated insulin secretion. Objectives: To study the genotype–phenotype correlations in patients with GLUD1 mutations.