Living with Classic homocystinuria
An inherited condition where the body cannot use homocysteine properly, affecting growth, eyes, blood clotting, and development.
Understanding Classic homocystinuria
It is caused by low or missing levels of an enzyme called CBS. Homocysteine and other toxic chemicals then build up in the blood and urine. Symptoms include poor growth and slow weight gain in infancy, nearsightedness, a shifted eye lens, a higher risk of blood clots, and developmental problems. GARD lists onset from childhood to adulthood.
Signs & symptoms
Symptoms vary from person to person. GARD lists these among the most common:
- Nearsightedness (myopia)
- Dislocated eye lens
- Blood clots in veins, arteries, or lungs
- Tall stature
- Crowded teeth
- Developmental problems
Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.
Diagnosis
- 1Talk with your doctor
Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.
- 2See a specialist
Specialists who may be involved include brain and nervous system specialists, eye disease specialists, genetic specialists and seizure and epilepsy specialists.
- 3Consider genetic testing
Changes in CBS are linked to this condition. Genetic testing and counseling can help confirm a diagnosis and explain what it means for your family.
- 4Connect with expert centers
HCU Network America and Epilepsy Foundation may keep lists of experts for this condition.
Care & treatment
- Care team
- Brain and nervous system specialists (neurologists); Eye disease specialists (ophthalmologists); Genetic specialists (geneticists); Seizure and epilepsy specialists (epileptologist)
- Expert care
- Expert lists: HCU Network America, Epilepsy Foundation
- Treatment
- GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
- Research
- Clinical trials and observational studies may be options. See the research section below.
General information, not medical advice. Your care team makes the decisions.
Everyday life
Living with a rare condition is easier with support.
- Connect with HCU Network America and other patient organizations
- Keep notes on symptoms, changes and questions for appointments
- Ask about patient registries that help research
- Look into financial aid and travel resources for care visits
Quick facts
GARD says changes in the CBS gene cause this condition. It is autosomal recessive, so a child inherits a changed copy of the gene from each parent.
Also known as: cbs deficiency; cystathionine beta-synthase deficiency; deficiency of beta-thionase; deficiency of methylcysteine synthase; deficiency of serine sulfhydrase; homocystinuria due to cbs deficiency
Patient organizations
- HCU Network AmericaClassic homocystinuria · United States
- flokClassic homocystinuria · United States
- Epilepsy FoundationEpilepsy · United States
You are more than your diagnosis
Perspectives from people navigating life with Classic homocystinuria.
Explore research for Classic homocystinuria
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