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Start free with EleplanDihydropteridine reductase deficiency
ORPHA:226Clinical subtype
Also called Hyperphenylalaninemia due to dihydropteridine reductase deficiency · PKU type 2 · Phenylketonuria type 2
What it is
A rare form of hyperphenylalaninemia due to tetrahydropterin (BH4) recycling deficiency, leading to central dopamine and serotonin deficiency, clinically characterized by infantile-onset neurological disease of variable severity ranging from mild forms with minor neurological development to severe forms with hypotonia, developmental delay, complex movement disorder dominated by dystonia or dystonia parkinsonism. Some patients may present refractory neurological symptoms like a degree of developmental delay, epilepsy and brain abnormalities.
Key facts
- Age of onset
- Infancy, Neonatal
- Inheritance
- Autosomal recessive
- Classified as
- Clinical subtype
Recorded for the broader condition
- Prevalence
- 1-9 / 1 000 000Hyperphenylalaninemia due to tetrahydrobiopterin deficiency
Orphanet records these for the broader condition rather than for this specific form. They are a starting point, not a figure for this subtype — subtypes often differ, and some are defined by being rarer than the condition they sit under.
Signs and symptoms
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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