Summary

The present report concerns the first case of a spontaneous arterial coronary dissection in adult onset homocystinuria leading to a premature myocardial infarct. The patient had also presented an unexplained lower limb venous thrombosis at the age of 41. A carotid artery thrombosis was found at the aged of 61 during the investigations for facial nerve palsy. The diagnosis of homocystinuria was delayed as it was only performed 20 years after the first thrombotic event. From observation, a pectus carinatum was the only clinical characteristic that could be related to homocystinuria phenotype. Cystathionine β-synthase (CBS) gene analysis showed compound heterozygous mutations. After 3 months of pyridoxine, the plasma homocysteine level was totally normalised.