RT Journal A1 SMITH DW T1 'prune belly' syndrome-reply JF American Journal of Diseases of Children JO American Journal of Diseases of Children YR 1979 FD June 1 VO 133 IS 6 SP 658 OP 658 DO 10.1001/archpedi.1979.02130060098032 UL http://dx.doi.org/10.1001/archpedi.1979.02130060098032 AB In Reply.—The thoughts of Drs Kroovand and Perlmutter express the predominant opinion of the past relative to the pathogenesis of the "prune belly" syndrome. Our hypothesis, that the most common pathogenesis is early urethral obstruction, will be published in detail in the near future.1 Severe early urethral obstruction results in a host of secondary biomechanical deformations as a consequence of the back pressure. The problem in bladder and urethral musculature and its partial replacement by collagen is the result of the distensile pressure. The same is true for the variable impact of gross bladder distension on abdominal musculature. These deductions are made possible by the evaluation of embryos and fetuses who had severe urethral obstruction that was lethal in fetal life, which would seem to be the most common outcome. To survive to be born and be evaluated by the urologist, the individual with severe urethral obstruction must