In a study of pedigrees of ten families, an increased frequency of ureteral reflux was found. Some members with ureteral reflux do not show any other symptoms. The distribution of affected individuals in sibships suggests a dominant gene, but the fact that affected offspring are frequently found in families of two nonaffected parents contradicts this assumption. The involvement of a dominant gene with incomplete expression is tentatively proposed.
Miller HC, Caspari EW. Ureteral Reflux as Genetic Trait. JAMA. 1972;220(6):842–843. doi:10.1001/jama.1972.03200060066012