RecruitingNCT00005909
Metabolic
Alkaptonuria
Also known as AKU, homogentisate dioxygenase deficiency, ochronosis, HGD deficiency
Alkaptonuria is a rare inherited disorder of tyrosine metabolism caused by deficiency of homogentisate dioxygenase (HGD), leading to accumulation of homogentisic acid (HGA). Over decades, HGA deposits in connective tissue cause ochronosis â
1
studies recruiting now
as of 7 Sept 2026
10
studies registered in total
as of 7 Sept 2026
1
countries with a recruiting site
as of 7 Sept 2026
14 Jun 2000
most recent study posted
among recruiting studies
Recruiting trials
Showing the 1 most recently updated recruiting study, as recorded 7 Sept 2026. Live status on each study page.
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About Alkaptonuria
Alkaptonuria is a rare inherited disorder of tyrosine metabolism caused by deficiency of homogentisate dioxygenase (HGD), leading to accumulation of homogentisic acid (HGA). Over decades, HGA deposits in connective tissue cause ochronosis — a blue-black pigmentation of cartilage, tendons, and sclerae — and leads to severe early-onset osteoarthritis affecting the spine and large joints. Nitisinone (Orfadin), approved in Europe for AKU, significantly reduces HGA levels.
Common clinical features
Dark urine on standingOchronosis (pigment deposits)Early-onset osteoarthritisSpinal stiffnessAortic stenosisRenal and prostate stonesTendon rupture
From Orphanet’s phenotype annotations (CC BY 4.0). Not a complete list.
Treatments being studied
1 in clinical development, from Open Targets (CC BY 4.0). Not medical advice.
Phase 3Nitisinone (Nitisinone mdk (previously nitisinone mendelikabs))
Before you apply
Things trial teams commonly ask about for Alkaptonuria. Not eligibility rules; those are set by each study.
- Nitisinone (NTBC) is approved in Europe — trials may focus on dose optimization, long-term joint outcomes, or combination approaches
- Urinary homogentisic acid (HGA) excretion is the primary biomarker — 24-hour urine HGA measurement is standard at screening
- Joint disease severity scoring (AKU Society's AKU Severity Score Index) is used as an eligibility and outcome measure
- AKU is very rare — contact the DevelopAKUre consortium and AKU Society for trial matching assistance
Related conditions
Information, not medical advice. Trial listings are shown as recorded on ClinicalTrials.gov; whether any study is right for you is a decision for you and your clinicians, and eligibility is decided by each research team. Disease information from Orphanet (CC BY 4.0).