This gene encodes a secreted ligand of the TGF-beta (transforming growth factor-beta) superfamily of proteins. Ligands of this family bind various TGF-beta receptors leading to recruitment and activation of SMAD family transcription factors that regulate gene expression. The encoded preproprotein is proteolytically processed to generate each subunit of the disulfide-linked homodimer. This protein regulates heart development and adipogenesis. Homozygous knockout mice die in utero, while a conditional knockout mouse exhibits defects in heart development. Transgenic mice overexpressing this gene in a neuron-specific manner exhibit a phenotype resembling the rare hereditary connective tissue disease, fibrodysplasia ossificans progressiva. [provided by RefSeq, Jul 2016]