Four rare gene mutations can be a key to a healthy heart. Researchers at Massachusetts General Hospital found that these mutations “all cripple the same gene,” and the result is linked to lower triglyceride levels that lowered the risk of coronary heart disease by 40%.

Researchers say this falls in line with recent thought that high triglyceride levels, instead of low HDL levels, cause heart disease. “It has long been presumed that low HDL is the causal factor in heart disease and triglycerides are along for the ride,” lead researcher Sekar Kathiresan said in a statement.