Cardiomyopathy and arrhythmia are diseases with significant genetic linkage. Cardiac myosin binding protein-C (cMyBP-C) is a myofilament associated protein with a C-terminal composed of repeating immunoglobulin (Ig) and fibronectin III (FnIII) domains that bind to the myosin thick filaments and titin. Truncating mutations in the C-terminal of MyBP-C prevent myofilament incorporation and resulting in degradation of the truncated protein and is a major cause of hypertrophic cardiomyopathy. Myosin-binding protein-H like (MyBP-HL) is a recently identified protein, is structurally related to cMyBP-C. Both cMyBP-C and MyBP-HL contain repeated C-terminal Ig and FnIII domains that bind to myosin. MyBP-HL is different in that it is primarily expressed in the atria where it interacts with the myofilament. A MyBP-HL premature stop mutations has been linked to ventricular conduction system abnormalities, atria enlargement, and dilated cardiomyopathy (DCM) in humans. The gnomAD database reports 9 stop gained mutations in MYBP-HL in humans including: Gln29, Trp54, Arg113, Tyr123, Trp158, Trp192, Lys250, Arg255, and Tyr307. Prior investigation modeled the MyBP-HL Arg255 mutation and showed no MyBP-HL localization to the myofilament, as seen in truncating mutations in cMyBP-C.