Hyperinsulinism/hyperammonemia (HI/HA) syndrome is considered as the second most common type of hereditary HI. Correlation of genotype and phenotype in HI/HA syndrome has been described in several studies. We present three Serbian patients with HI/HA syndrome with emphasis on a possible correlation between genotype and clinical manifestations. Patient 1 was heterozygous for a de novo mutation p.S445L in the GLUD1 gene, while patients 2 and 3 (son and mother) both carry the p.R221C mutation. Early onset of hypoglycaemia with generalized seizures was recorded in infancy in all three patients. The two male patients had mild developmental delay, while the female patient presented with epilepsy. Analysis of Serbian patients with HI/HA syndrome confirms the association of p.S445L and p.R221C mutations with hypoglycaemic seizures noted within the first three months of life and with subsequent risk for cognitive impairment and/or epilepsy.
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http://dx.doi.org/10.4274/jcrpe.2436 | DOI Listing |
AACE Clin Case Rep
April 2023
Department of Medicine, Section of Endocrinology, Marshall University School of Medicine, Huntington, West Virginia.
Background/objective: To illustrate an unusual case of type 2 diabetes mellitus (T2DM) developing many years after the diagnosis of hyperinsulinism hyperammonemia (HI/HA) syndrome.
Case Report: This article reports about a 36-year-old female with a history of congenital hyperinsulinism due to HI/HA syndrome, which was diagnosed in infancy. The patient presented with hypoglycemia and seizures as an infant and was treated with diazoxide and a low-protein diet for many years with reduction in her hypoglycemic events.
J Inherit Metab Dis
July 2023
Morris Kahn Laboratory of Human Genetics at the Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences and National Institute for Biotechnology in the Negev, Ben Gurion University, Beer Sheva, Israel.
Hyperinsulinism/hyperammonemia (HI/HA) syndrome has been known to be caused by dominant gain-of-function mutations in GLUD1, encoding the mitochondrial enzyme glutamate dehydrogenase. Pathogenic GLUD1 mutations enhance enzymatic activity by reducing its sensitivity to allosteric inhibition by GTP. Two recent independent studies showed that a similar HI/HA phenotype can be caused by biallelic mutations in SLC25A36, encoding pyrimidine nucleotide carrier 2 (PNC2), a mitochondrial nucleotide carrier that transports pyrimidine and guanine nucleotides across the inner mitochondrial membrane: one study reported a single case caused by a homozygous truncating mutation in SLC25A36 resulting in lack of expression of SLC25A36 in patients' fibroblasts.
View Article and Find Full Text PDFJ Pediatr Endocrinol Metab
February 2023
Department of Endocrinology and Metabolism of The Child's Health National Institute, Instituto Nacional de Salud del Niño, Lima, Peru.
Objectives: Congenital hyperinsulinism (HI) is a heterogeneous clinical disorder with great variability in its clinical phenotype, and to date, pathogenic variants in 23 genes have been recognized. Hyperinsulinism-hyperammonemia syndrome (HI/HA) is the second most frequent cause of this disease that shows an autosomal dominant pattern and is caused by an activating mutation of the gene, which responds favorably to the use of diazoxide. HI/HA syndrome presents with fasting hypoglycemia; postprandial hypoglycemia, especially in those with a high protein content (leucine); and persistent mild hyperammonemia.
View Article and Find Full Text PDFEndocr Connect
April 2023
Department of Paediatric Endocrinology, Great Ormond Street Hospital, London, UK.
Background: Hyperinsulinism/hyperammonemia (HI/HA) syndrome is the second most common type of congenital hyperinsulinism caused by an activating GLUD1 mutation.
Objective: The aim of this study was to determine the clinical profile and long-term neurological outcomes in children with HI/HA syndrome.
Method: This study is a retrospective review of patients with GLUD1 mutation, treated at two centers in the UK and Russia, over a 15-year period.
Orphanet J Rare Dis
June 2022
Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3500 Civic Center Boulevard, Philadelphia, PA, 19140, USA.
Background: Hyperinsulinism hyperammonemia (HI/HA) syndrome is caused by activating mutations in GLUD1, encoding glutamate dehydrogenase (GDH). Atypical absence seizures and neuropsychological disorders occur at high rates in this form of hyperinsulinism. Dysregulated central nervous system (CNS) glutamate balance, due to GDH overactivity in the brain, has been hypothesized to play a role.
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