Homocystinuria Clinical Trials and Treatments

Homocystinuria encompasses three biochemically distinct disorders of homocysteine metabolism, the most common being cystathionine beta-synthase (CBS) deficiency, an autosomal recessive enzymatic defect. CBS deficiency impairs the conversion of homocysteine to cystathionine in the transsulfuration pathway, resulting in severe elevation of homocysteine in plasma and urine. Elevated homocysteine causes endothelial damage, increased thrombotic risk, lens dislocation (often the presenting sign), and neurological complications including developmental delay and psychiatric manifestations.

The most common symptoms of Homocystinuria include Lens dislocation (ectopia lentis), usually downward, Myopia and astigmatism, Intellectual disability if untreated, Thrombosis and blood clots, Marfanoid body habitus with arachnodactyly, among others. Homocystinuria affects approximately 1 in 340,000 births (cystathionine beta-synthase deficiency). Symptoms can range from mild to severe and may vary between individuals.

Trial Friend lists all active clinical trials for Homocystinuria from ClinicalTrials.gov, with eligibility criteria translated into plain English. Patients can filter by trial phase and recruitment status, search by location, and use the Match Me tool to score trials against their profile. Homocystinuria treatment is expanding beyond vitamin B supplementation and dietary protein restriction. Clinical trials are evaluating novel therapies targeting metabolic pathways responsible for elevated homocysteine, offering potential breakthrough approaches.

As of September 2026, Trial Friend's curated drug index does not include an FDA-approved treatment specific to Homocystinuria. The Treatments section of this page checks FDA drug labels live and lists any approved drug whose label names the condition, and the trials listed below cover the investigational options.

Homocystinuria is caused by variants in the CBS, MTHFR, MTR, MTRR and MMADHC genes. Classic homocystinuria is CBS deficiency; the remethylation-defect genes are rare causes.

It is inherited in an autosomal recessive pattern: both parents are usually unaffected carriers, and each pregnancy has a 1 in 4 chance of an affected child. The condition affects approximately 1 in 340,000 births (cystathionine beta-synthase deficiency). Genetic testing confirms the diagnosis.

Yes. Genetic testing for Homocystinuria looks at the CBS, MTHFR, MTR, MTRR and MMADHC genes. Classic homocystinuria is CBS deficiency; the remethylation-defect genes are rare causes.

It is inherited in an autosomal recessive pattern: both parents are usually unaffected carriers, and each pregnancy has a 1 in 4 chance of an affected child.

A confirmed variant establishes the diagnosis and is often required to enroll in gene-specific trials. The labs currently offering the test are listed in the Genetic Testing section of this page, pulled live from the NIH Genetic Testing Registry. A genetic counselor can help interpret the result and decide which relatives should be tested.

Eligibility for Homocystinuria clinical trials depends on factors like age, diagnosis, treatment history, and overall health. Each trial sets its own inclusion and exclusion criteria. Trial Friend translates these requirements from medical language into plain English so patients can review them more easily. The Match Me tool can score your profile against active trials to help identify studies that may be a fit.

Participating in a Homocystinuria clinical trial typically involves scheduled visits, medical tests, and close monitoring by a research team. Depending on the study phase, you may receive an investigational treatment, a placebo, or the current standard of care. Trials may last from a few weeks to several years. Study participation is voluntary, and you can withdraw at any time.