EBSTEINS MALFORMATION OF THE TRICUSPID-VALVE - GENETIC AND ENVIRONMENTAL-FACTORS

Ebstein's anomaly is a specific structural deformity of the tricuspid valve, and its rarity has hampered etiologic evaluation. Cases of Ebst ein's anomaly registered in the Baltimore Washington Infant Study (BWI S), a regional case-control study of cardiovascular malformations (CVM ) in infancy, are reviewed. Between 1981 and 1989 a total of 4,390 CVM cases, including 47 Ebstein cases, and 3,572 controls were registered . The prevalence of Ebstein's anomaly was 5.2 per 100,000 livebirths. Additional cardiac anomalies were present in 38.3% of Ebstein cases. N on-cardiac malformations were present in 19.1% of Ebstein cases vs. 25 .5% of other CVM, and 1.7% of controls. Case-fatality by 1 year of age was 23.4% in Ebstein vs. 18.1% in other CVM. Interviews of parents of Ebstein cases, other CVM, and controls (n = 44, 3,335, and 3,572, res pectively) elicited information on family history of malformations, ma ternal illnesses, reproductive history, therapeutic drugs, parental li festyle, and environmental exposures during the periconceptional perio d. Case-control analyses suggest genetic, reproductive, and environmen tal risk factors: twins [odds ratio (OR) 8.2, 95% confidence interval (CI) 2.6-25.3]; family history of CVM (OR 6.4, 95% CI 1.8-22.2); white race (OR 2.9 with non-whites as reference, 95% CI 1.2-7.0); previous miscarriages (OR 2.0, 95% CI 1.2-3.3); maternal exposure to benzodiaze pines (OR 5.4, 95% CI 1.5-19.1); and varnishing (OR 3.4, 95% CI 1.3-9. 1). Additional multicenter investigations are warranted to elucidate t he role of genetic, reproductive, and environmental factors in the eti ology of this anomaly. (C) 1994 Wiley-Liss, Inc.