Nonneural congenital abnormalities concurring with myelomeningocele: Report of 17 cases and review of current theories

Objective: Meningomyelocele (MMC) is a common central nervous system birth defect. Various congenital and acquired abnormalities have been reported with MMC, some of which are secondary to the pathophysiology and some are morbidities of the underlying disease. The aim of this study was to discuss current possible theories explaining diverse anomalies/abnormalities seen in a series of 390 patients with MMC. Methods: A retrospective study was performed using the records of 390 patients with MMC at Children's Hospital Medical Center in Tehran, Iran, from January 2001 to January 2007. A series of 17 cases of MMC with attributed organ anomalies, not explained by a causal effect of the underlying disorder, were compiled. There were 3 cardiac anomalies including ventricular septal defect, pulmonary artery atresia and tetralogy of Fallot, 4 musculoskeletal malformations, consisting of missing rib, polydactylia and complex distal limb anomaly, 4 urological anomalies such as bladder exstrophy, horseshoe kidney and dysplastic kidneys, 2 occipital encephaloceles, 2 congenital adrenal hyperplasia patients with ambiguous genitalia, 1 omphalocele, 1 albinism and 1 Klippel-Feil syndrome. A review of the literature and discussion explaining each of these observations, have been performed and some possible theories have been proposed.Conclusions: Although various organ anomalies with different embryological origin had been observed and reported with MMC, it is difficult to explain their development using one of the current theories of MMC formation. It could be attributed to a possible genetic defect or merely an incidental finding. A teratological insult during the embryogenic phase would be an alternative assumption.