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Start free with EleplanHyperinsulinism-hyperammonemia syndrome
ORPHA:35878Disease
Also called HI/HA syndrome
What it is
A rare diffuse form of congenital hyperinsulinism characterized by an excessive/ uncontrolled insulin secretion (inappropriate for the level of glycemia), chronic hyperammonemia and recurrent episodes of hypoglycemia induced by fasting and protein rich meals. Epilepsy and cognitive deficit, which are unrelated to hypoglycemia but possibly related to the chronic hyperammonemia, may also occur. This disorder is usually responsive to diazoxide treatment.
Key facts
- Age of onset
- Infancy, Neonatal
- Inheritance
- Autosomal dominant
- Classified as
- Disease
Signs and symptoms
Common30–79%
10- Attention deficit hyperactivity disorder
- EEG with generalized epileptiform discharges
- Fasting hyperinsulinemia
- Generalized non-motor (absence) seizure
- Generalized-onset seizure
- Global developmental delay
- Hyperinsulinemic hypoglycemia
- Increased urine alpha-ketoglutarate concentration
- Intellectual disability, moderate
- Specific learning disability
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
Gene
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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