hyperinsulinism-hyperammonemia syndrome
Findings
No curated finding names hyperinsulinism-hyperammonemia syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Hyperinsulinism-hyperammonemia syndrome (HIHA) is a frequent form of diazoxide-sensitive diffuse hyperinsulinism, characterized by an excessive/ uncontrolled insulin secretion (inappropriate for the level of glycemia), asymptomatic hyperammonemia and recurrent episodes of profound hypoglycemia induced by fasting and protein rich meals, requiring rapid and intensive treatment to prevent neurological sequelae. Epilepsy and cognitive deficit that are unrelated to hypoglycemia may also occur.
Definition from the Mondo Disease Ontology (MONDO:0011717), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal dominant inheritance
- Onset and course
- Infantile onset · Neonatal onset
HPO, annotations 2026-09-02
Features
17 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Asymptomatic hyperammonemiaHPOHP:0008162
- 5 of 5 reported patients
- Very frequent (80% to 99% of cases)
- Hyperinsulinemic hypoglycemiaHPOHP:0000825
- 5 of 5 reported patients
- Frequent (30% to 79% of cases)
- Failure to thriveHPOHP:0001508
- 4 of 5 reported patients
- Reactive hypoglycemiaHPOHP:0012051
- Very frequent (80% to 99% of cases)
- Attention deficit hyperactivity disorderHPOHP:0007018
- Frequent (30% to 79% of cases)
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- GLUD1HGNC:4335
- Definitive · ClinGen · Autosomal dominant · 2020
- Definitive · G2P · Autosomal dominant · 2015
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal dominant · 2020
- Strong · PanelApp Australia · Autosomal dominant · 2025
- Supportive · Orphanet · Autosomal dominant · 2021
Where it sits
Other names
6 names
Resolves to: hyperinsulinism-hyperammonemia syndrome
- Also called
- GDH hyperinsulinismGLUD1 hyperinsulinismglutamate dehydrogenase 1 hyperinsulinismhi/HA syndromehyperinsulinemic hypoglycemia, familial, type 6hyperinsulinism/hyperammonemia syndrome