Description of the characteristics of cases with noncontiguous neural tube defects identified in a series of consecutive births.

Van Allen et al. [(1973) Am. J. Med. Genet. 47:723-743] provided evidence for multisite closure of the neural tube in humans. Reynolds et al. [(1995) Proceedings of the Greewood Genetic Center 14:70-71] and Seller [(1995) J. Med. Genet. 32:205-207] described 13 and seven cases of noncontiguous neural tube defects (NTDs) respectively and concluded that the presence of noncontiguous NTDs cannot be explained on the basis of the model of a single initiation site with bidirectional closure. Here we present a series of 14 consecutive infants with noncontiguous NTDs, describing their characteristics. These show that noncontiguous NTDs are clinically heterogeneous, may have differences in sex ratio, and could have causal heterogeneity. The different combinations of closure failure defects have shown proportions in our population that are different from those in the populations studied by Reynolds et al. and Seller.

Lethal short rib-polydactyly syndromes: further evidence for their overlapping in a continuous spectrum.

We report two new unrelated infants with short rib-polydactyly syndrome (SRPS) whose clinical and radiological features overlap the four established forms of lethal SRPS, so that it is difficult to classify them into any one particular type. One of the babies had one of the most radiologically severe SRPS ever published. The patients presented here support the previously reported hypothesis that this group of disorders might be a continuous spectrum rather than separate entities.

Trisomy 13 in the child of two carriers of a 13/15 translocation.

We report on an infant girl with trisomy 13 resulting from an inherited 13-15 Robertsonian translocation identified in a family from a small Spanish village of only 2,100 inhabitants. Both parents and several other relatives had a balanced 13-15 translocation.