Caring for someone with this diagnosis? Eleplan keeps diagnoses, medications, documents and every specialist in one plan.
Start free with EleplanHyperlysinemia
ORPHA:2203Disease
Also called Hyperlysinemia type I · Lysine alpha-ketoglutarate reductase deficiency
What it is
A rare autosomal recessive disorder of lysine metabolism characterized by elevated levels of lysine in the cerebrospinal fluid and blood. Hyperlysinemia type I has been associated with a highly variable phenotype including seizures, hypotonia, and mild psychomotor delay, although isolated hyperlysinemia is probably a benign condition.
Key facts
- Age of onset
- All ages
- Inheritance
- Autosomal recessive
- Classified as
- Disease
Signs and symptoms
Common30–79%
22- Abnormal CSF ornithine concentration
- Abnormal enzyme/coenzyme activity
- Argininuria
- Atypical behavior
- Cystinuria
- Decreased CSF arginine concentration
- Decreased urine alpha-ketoglutarate concentration
- Delayed speech and language development
- EEG with spike-wave complexes
- Floppy infant
- Global developmental delay
- Hyperammonemia
- Hyperlysinemia
- Hyperlysinuria
- Hypoornithinemia
- Increased CSF lysine concentration
- Intellectual disability
- Microcephaly
- Neurodevelopmental delay
- Seizure
- Short attention span
- Short stature
Sometimes5–29%
35- Abnormal facial shape
- Abnormality of movement
- Brisk reflexes
- Clumsiness
- Craniosynostosis
- Depressed nasal ridge
- Dysmetria
- Dysphagia
and 27 more in this range
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.
Powered by Eleplan
A rare diagnosis is just the start. Eleplan keeps the whole care plan in one place.
Diagnoses, medications, documents, appointments, and the whole care team — organized and always in sync, so you are not retelling the same story to every new specialist. With Ellie, your AI care assistant, on top of it. Free to start.