Effects of Exercise on Metabolic Parameters in Classical Homocystinuria

Inclusion Criteria for subjects: * Informed consent as documented by signature * Confirmed biallelic mutation of cystathionine beta-synthase deficiency gene (homozygous or compound heterozygous) in an accredited Laboratory * Continuation of their regular treatment under same dose (e.g. vitamin B6, B9 and B12, betaine) as prior to the study inclusion Inclusion Criteria for controls: \- Healthy Exclusion Criteria: * Any clinically instable concomitant disease * Individuals with acute cardiac events, syncope, rhythm disturbances or unstable hypertension in the past 6 months * Individuals with vitamins B9 or B12 deficiencies * Homocysteine \> 100 µmol/l (for subjects) * Homocysteine \> 20 µmol/l (for controls)