- TERC is not a major gene in human neural tube defects. Benz, L.P., Swift, F.E., Graham, F.L., Enterline, D.S., Melvin, E.C., Hammock, P., Gilbert, J.R., Speer, M.C., Bassuk, A.G., Kessler, J.A., George, T.M. Birth defects research. Part A, Clinical and molecular teratology. (2004)