NT5C1A and Tricuspid regurgitation: An echocardiogram revealed an ejection fraction of 56%, with trace mitral regurgitation and tricuspid regurgitation. The extended myositis panel, which tested for antibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) and cytosolic 5'-nucleotidase 1A (CN1A), all returned negative results.