Cholesterol is a vital causal factor and focus of research into heart diseases, however the involvement of triglycerides remains unclear. We recently reported a patient suffering from severe congestive heart failure and needing cardiac transplantation. Massive accumulation of triglycerides was noted in coronary atherosclerotic lesions as well as in the myocardium. We named this phenotype"triglyceride deposit cardiomyovasculopathy (TGCV)". The patient was identified as homozygous for a genetic mutation in the adipose triglyceride lipase (ATGL), an essential molecule for hydrolysis of intracellular triglycerides. In this paper, we describe clinical characteristics of ATGL deficiency and discuss what we can learn from this disorder.