MAJOR CONGENITAL-MALFORMATIONS IN DOWN-SYNDROME

We studied major malformations in 5,581 infants with Down syndrome (DS ) from three registers of congenital malformations. The prevalence at birth of 23 different malformations was compared with the program-spec ific rates for each malformation in non-DS infants. An about 300 times risk increase was Seen for annular pancreas, cataracts and duodenal a tresia and an about 100 times risk increase for megacolon and choanal atresia. Esophageal, anal and small bowel atresia, preaxial polydactyl y, and omphalocele all showed risk increases between 10 and 30 times. Statistically significantly elevated risk ratios around 3-5 were seen for cleft palate, cleft lip/palate, and limb deficiencies. No increase d risk was seen for neural tube defects, hydrocephaly, microtia, renal agenesis or severe dysgenesis, hypospadias or polydactyly other than preaxial. Oral clefts were more often present in DS in the Swedish mat erial than in the other two materials. Cardiac defects were registered in 26% of all cases (varying between programs) but 28% of the cardiac defects were unspecified. DS infants born to women younger than 25 ye ars had a significantly increased risk for megacolon and there was a t rend of increasing risk for esophageal or anal atresia with maternal a ge. A decreased risk for cardiac defect in DS infants born to teenage mothers was found, quite pronounced for endocardial cushion defects an d ventricular septum. defects. There were no statistically significant differences in the sex distribution of specific malformations in infa nts with DS and in non-DS infants. (C) 1996 Wiley-Liss, Inc.