The case of an infant with neuroblastoma syndactyly and rib anomalies is presented. Twenty‐six cases of neuroblastoma have been recorded in which a variety of developmental defects have been found. The possible etiologic implications of the association of developmental defects with neuroblastoma are discussed. The absence generally of familial aggregation of neuroblastoma or of a specific pattern of associated developmental defects is consistent with the hypothesis that most cases of neuroblastoma result from sporadic postzygotic disorders. That germinal mutation may also rarely lead to neuroblastoma is suggested by the existence of four affected siblings in a single report.