Modulates the activity of key transcription factors involved in cardiogenesis. Expressed at highest levels in heart, and at lower levels in brain, spleen, lung, liver and kidney. First detected at 7.5 dpc in the mesendoderm that forms the anterior gut and the heart. At midgestation, expressed in the limb bud ectoderm and other specialized epithelia, as well as in the branchial arches and some neural crest derivatives. In the heart, expression initiates in the myocardial plate at the presomitic stage, with highest levels in the anterior myocardium. During heart chamber formation, expressed transiently in the right ventricle, atrioventricular canal and inflow tract. In the limb bud, expression is restricted to the ventral ectodermal compartment and the apical ectodermal ridge. Mice overexpressing Lbh in heart exhibit severe cardiac abnormalities and dysfunction. Belongs to the LBH family.