HERITABILITY AND BIOCHEMISTRY OF GANGLIOSIDOSIS IN EMUS (DROMAIUS-NOVAEHOLLANDIAE)

The progeny of two emu breeder pairs, which had a history of producing offspring with gangliosidosis, were monitored for 15 mo. DNA fingerpr inting revealed that individuals in each breeder pair were not related to each other One breeder pair had 13 progeny that reached or exceede d the age of 1 mo, and six of these progeny developed gangliosidosis. The mean age at which these affected emus were euthanatized, with dist inct neurologic disease, or died was 5.7 mo. The second emu pair had 1 3 progeny, seven of which developed gangliosidosis, with a mean age of euthanasia/death of 4.6 mo. Affected emus died or were euthanatized f rom 2 to 8 mo of age. The primary clinical sign in the affected emus w as mild to severe ataxia. Severe hemorrhage into the body cavity or th e muscles of the thigh was noted in 8 of 13 of the affected emus. Brai n ganglioside levels were evaluated in six of the affected emus and si x controls. Significant increases (P < 0.05) in gangliosides GM1 and G M3 were noted, with 2.3- and 4.9-fold increases in these two gangliosi des, respectively, in affected emus. Furthermore, the diseased emu bra ins contained ganglioside GM2, whereas this monosialoganglioside was u ndetectable in the brains of normal controls. Total mean brain ganglio side sialic acid in affected emus was increased 3.3-fold in comparison with controls. Serum chemistries revealed elevated cholesterol and de creased uric acid levels in affected emus. Gangliosidosis in emus is a n inherited disease process that, in the current study, caused 50% mor tality in the progeny of two emu breeder pairs. The elimination of thi s lethal gene from emu breeder stock is essential for the long-term ec onomic viability of the United States emu industry.