Congenital radial and thumb aplasia in a neonatal owl monkey (Aotus nancymaae).

This report describes congenital radial and thumb aplasia in a neonatal owl monkey. Congenital limb deformities in human neonates and Old World primate species have been well characterized. The many probable causes of these congenital defects in skeletal structure include fetal exposure to environmental toxins and genetic influences. In nonhuman primates, the cause frequently remains undetermined. In the case we present, the neonate presented for examination because of inability to cling to the dam. The forelimbs were contracted distally, and thumbs were absent. Radiographs indicated complete radial aplasia and other skeletal abnormalities. This description is the fi rst case study of congenital radial and thumb aplasia in a New World primate species.