has part has part has_part characteristic of has modifier abnormal visceral yolk sac morphology absent visceral yolk sac csmith MP:0011206 absence of the extraembryonic tissue membrane, formed from the visceral endoderm and the extraembryonic mesoderm, which is located ventral to the embryonic disc and is connected to the presumptive midgut of the embryo 2011-06-24T03:40:33Z MPheno.ontology abnormal absent visceral yolk sac