Funds are requested for partial support of the 9th FASEB Summer Research Conference on Folic Acid, Vitamin B12 and One Carbon Metabolism to be held from August 3- August 8, 2002 at Snowmass Village, Colorado. This conference offers a unique opportunity for productive, formal and informal interactions between clinician investigators, basic scientists and those involved in health and science policy. The participants represent a diverse and broad group of disciplines. The last seven conferences, which met every second year, were fully subscribed. The current conference will be limited to 210 participants. The requested funds will support the attendance of graduate students; resident physicians; postdoctoral fellows; and established national and international investigators. A detailed program, led by senior scientist, emphasizes the participation of junior scientists new to the field. Thus the topics selected cover basic sciences and clinical research with particular emphasis on the interaction and potential synergy between the two. The specific subjects include (1) One Carbon Metabolism, Enzymology and Regulation; (2) Folate-Dependent Enzymes: Mechanisms and Structure; (3) Mammalian Methionine Metabolism-Regulation of the Integrated Pathways; (4) Metabolic Studies of Human Metabolism; (5) S-adenosylhomocysteine - Synthesis and Regulatory Potential; (6) Inborn errors of Folate, Cobalamin and Methionine Metabolism; (7) Knock Out Mice as Models of Human Genetic Diseases; (8) One Carbon Metabolism and Neoplasia of the Liver and Colon; (9) The Pathophysiology of Homocysteine Toxicity. In addition, poster sessions and workshops supplement these formal sessions. The workshops will provide expert and current analyses of (1) Preliminary Reports from the Folate Supplementation and Intervention Trials; (2) Hyperhomocysteinemia and Cognitive Dysfunction; (3) The Clinical Value of Homocysteine determinations; (3) Changing criteria for cobalamin deficiency; and (5) The Mechanism of Hyperhomocysteinemia in Renal Failure. The format encourages discussions between the presenters and the fellows, residents and junior investigators in attendance. Similarly, the poster sessions also highlight the activities and the needs of the younger participants.