Specific CHDs showed highly variable but strong familial clustering in first-degree relatives, ranging from 3-fold to 80-fold compared with the population prevalence, whereas the crossover risks between dissimilar cases of CHD were weaker. Family history of any CHD among first-degree relatives accounted for a small proportion of CHD cases in the population.

No abstract

Background-Variation within a single gene might produce different congenital heart defects (CHDs) within a family, which could explain the previously reported familial aggregation of discordant CHDs. We investigated whether certain groups of discordant CHDs are more common in families than others.