A rare case of monozygotic iniodymic diprosopiasis in a German Holstein calf

Craniofacial duplication abnormity is a rare phenomenon in buiatric practice. This report attends to a male German Holstein calf which could be classified as a diprosopic iniodymus. A fetus exhibiting a doubled face was delivered after fetotomy. To our knowledge, this is the first description of diprosopiasis with two cranial cavities as well as two separate encephala in a calf showing the potential extent of duplication. Throughout this work also the question is answered of whether this malformation in a bovine species arose from one embryo or rather, there is a dizygotic background by genotyping of tissue samples from both parts of the diprosopus. Regarding etiology, not only hereditary dispositions including among others a failed function of the signaling molecule Sonic hedgehog mediating regulation of craniofacial morphogenesis, but also incompletely separated monozygotic twins are discussed.