Patterns in multimalformed babies and the question of the relationship between sirenomelia and VACTERL

Starting from a data base of over one million births investigated in 11 countries as a part of the Latin American Study of Congenital Malformations, 1,428 babies with three or more malformations without known pathogenesis or cause were studied. The objective was to search for statistically significant associations between defects and the delineation of new syndromes. One hundred and twenty-one patients presented an association between malformations of the digestive and urogenital systems involving mainly anal, renal, and genital anomalies, while 21 of them had 3 or more VACTERL defects. The frequencies of these defects were intermediate between those observed for VACTERL or sirenomelia, supporting the idea that these conditions have a similar pathogenesis. Statistical approaches like this one may be helpful in identifying processes and biological entities that may be missed using simple clinical observations.