Monarch Disease Ontology entry MONDO_0009352 (classic homocystinuria) can be described as follows. Classical homocystinuria due to cystathionine beta-synthase (CbS) deficiency is characterized by the multiple involvement of the eye, skeleton, central nervous system, and vascular system. Also known as: Homocystinuria due to Cystathionine Beta-Synthase Deficiency, cystathionine beta-synthase deficiency, homocystinuria due to cystathionine beta-synthase deficiency, homocystinuria, B6-responsive and nonresponsive types, thrombosis, hyperhomocysteinemic.