Sir.—I would like to make some comments about the article by Cain et al that appeared in the September issue of the Journal (128:377, 1974).
Inadvertently, the authors did not include in their review our article on the subject.1 In our article, reports on three kindreds (A, B, and C) with familial bilateral renal agenesis (BRA) are presented. We observed that BRA is a multifactorially determined disorder. Pathogenetically, it is viewed as a developmental field defect involving absence of both kidneys and ureters in all cases, and in other cases an associated spectrum of related field defects that range from absence of the uterus and vagina to sirenomelia. In BRA, Potter syndrome represents a symptomatic deformity complex due to oligohydramnios.
Two additional kindreds (D and E) in our article show that unilateral absence of a kidney may occur in relatives of a propositus with severe bilateral renal "adysplasia."