Symmetrical parapagus diprosopus: A comparative, computed tomographic, and pathoanatomical study of a new case in domestic pig.

BACKGROUND: Parapagus diprosopus are conjoined twins characterized by craniofacial duplication and only one body, representing one of the rarest types of these twins. Their occurrence has been recorded in different species of vertebrates, including humans, but few cases have been studied in domestic pigs. CASE: A pair of conjoined twin pigs was studied using x-rays, computed tomography, and necropsy. The abnormalities found were compared with those of the rare swine cases presented in the literature as well as with other species, and the different etiopathogenetic possibilities were addressed. The degree of duplication of the head bones decreased caudally, as did that of the structures of the central nervous system. In the two oral cavities, there was a complete cleft palate. All the cervical vertebrae and thoracic vertebrae up to T3 were partially duplicated. The heart and great vessels were normal, as were the other thoracic and abdominal organs. CONCLUSIONS: The conjoined twin pigs of this study are a case of parapagus diprosopus tetraophthalmus triotus, presenting the same pattern of abnormalities of human diprosopus and that of other species. The scarcity of detailed studies on craniofacial duplication in pigs and the lack of a definitive explanation on the etiology and pathogenesis of conjoined twins shows the need for further research and the publication of more cases.

Inborn Errors of Metabolism in Dogs: Historical, Metabolic, Genetic, and Clinical Aspects.

Inborn errors of metabolism are genetic disorders caused by a block in a metabolic pathway, affecting both humans and animals. Individually, they are rare diseases, but as a group they are relatively common. As most of them have recessive inheritance, a new case may seem like just a sporadic case. The high degree of inbreeding in dog breeds increases the frequency of heterozygotes in populations, maintaining mutations (variants) in healthy individuals and, consequently, increasing the risk of disease recurrence (homozygotes). General practitioners' familiarization with this subject is a significant factor in identifying new cases, contributing to increased knowledge about inborn errors of metabolism and their control. To help general practitioners, we use a clinical genetics approach covering key genetic, metabolic, diagnostic, and therapeutic aspects, offering an overview that integrates knowledge about these diseases in dogs and humans.