AGNATHIA IN A LAMB: RADIOLOGICAL AND GROSS OBSERVATIONS

Agnathia (Dysgnathia or Agnathia-Otocephaly - AO) is a lethal malformation complex of the first branchial arch characterized by absence of the mandible, microstomia, aplasia or hypoplasia of the tongue, and low-set or medially fused ears toward the midline. Aim of the paper is to describe the radiological and gross findings of the condition observed in a lamb occasionally occurred at Authors' attention. A male Comisana lamb was collected dead from the uterus of a Comisana sheep at the end of pregnancy during slaughtering. The lamb was sent frozen to the Unit of Veterinary Pathology of the University of Messina. Prior the dissection, was performed radiological finding. Externally the lamb had astomia, proboscis, lack of mandible, bilateral hypoplasia of the maxilla and slightly prominent fluctuant pharyngeal diverticulum. The pinnae of the ears were fused in the ventral midline (synotia) with a common athresic external auditory meatus, also confirmed by the contrastographic x-ray examination. The ocular orbits were ventromedial displaced with nearly fused eyes resembling synophtalmia. Direct radiographic evaluation, revealed the absence of the mandible, hyoid bones, timpanic bullae and hypoplasia of the maxilla. Contrastographic x-ray examination and the following dissection confirmed the presence of a laringo-pharyngeal diverticulum and dilation of the oesophagus. Based on radiological and gross findings, the malformation was classified as agnathia and associated to the type 4 malformation of the first branchial arch in sheep or "ateloprosopla. Authors discuss the possible pathogenic mechanisms of this condition, infrequently reported in veterinary practice, pointing out the importance of the knowledge of animal malformations in breeding management.