dihydropteridine reductase deficiency
Findings
No curated finding names dihydropteridine reductase deficiency yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Dihydropteridine reductase (DHPR) deficiency is a severe form of hyperphenylalaninemia (HPA) due to impaired regeneration of tetrahydrobiopterin (BH4), leading to decreased levels of neurotransmitters (dopamine, serotonin) and folate in cerebrospinal fluid, and causing neurological symptoms such as psychomotor delay, hypotonia, seizures, abnormal movements, hypersalivation, and swallowing difficulties.
Definition from the Mondo Disease Ontology (MONDO:0009862), read 2026-09-29. CC BY 4.0.
Features
5 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.
- Diminished tissue dihydropteridine reductase activityHPOHP:6000966
- 2 of 2 reported patients
- DysphagiaHPOHP:0002015
- Very frequent (80% to 99% of cases)
- Global developmental delayHPOHP:0001263
- Very frequent (80% to 99% of cases)
- Intellectual disabilityHPOHP:0001249
- Very frequent (80% to 99% of cases)
- MicrocephalyHPOHP:0000252
- Very frequent (80% to 99% 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.
- QDPRHGNC:9752
- Definitive · ClinGen · Autosomal recessive · 2018
- Definitive · G2P · Autosomal recessive · 2015
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2018
- Strong · PanelApp Australia · Autosomal recessive · 2025
- Supportive · Orphanet · Autosomal recessive · 2021
Where it sits
Other names
7 names
Resolves to: dihydropteridine reductase deficiency
- Also called
- 6,7-dihydropteridine reductase activity diseasedisorder of 6,7-dihydropteridine reductase activityhyperphenylalaninemia due to dihydropteridine reductase deficiencyhyperphenylalaninemia, BH4-deficient Chyperphenylalaninemia, Bh4-deficient, type Cphenylketonuria type 2PKU type 2