CLINICAL AND MORPHOLOGIC FINDINGS OF FAMILIAL GOITER IN BONGO ANTELOPE (TRAGELAPHUS-EURYCERUS)

Inherited defects of thyroglobulin synthesis resulting in congenital g oiter are well described in certain breeds of domestic ungulates and i n human beings. Goiter associated with synthesis of an abnormal thyrog lobulin and the presence of thyroidal albumin was identified in five c losely related bongo antelopes (Tragelaphus eurycerus). The goiter had an adult onset, and the affected bongos appeared to remain euthyroid with normal serum T3 and T4 values, normal serum cholesterol concentra tions, and nonelevated concentrations of circulating thyroid stimulati ng hormone (TSH). Goitrous bongos had significant reproductive difficu lties, including reduced cyclic activity and prolonged gestations, but were otherwise normal. Over the course of the disease, the thyroid gl ands greatly enlarged (up to 10 x 20 cm) and became polycystic. Micros copically, there was an admixture of giant colloid-filled follicles an d follicles of normal size lined with variable follicular epithelium r anging from squamoid to mildly to moderately hyperplastic. The pathoge nesis of goiter in the bongo may reflect a mixture of genetic predispo sition coupled with environmental factors, including a period of expos ure to a goitrogen.