Required for myofibril assembly and outgrowth of the cardiac chambers in the developing heart (By similarity). Appears to be catalytically inactive, showing no activity against O-acetyl-ADP-ribose (PubMed:17075046). Expressed in the embryonic heart at E11.5. Belongs to the ADP-ribosylglycohydrolase family. Although it belongs to the ADP-ribosylglycohydrolase family, lacks the metal-binding and substrate-binding residues, suggesting that it has no hydrolase activity.