Re: Consanguinity and isolated atrial septal defect in the North East of Iran.

To the Editor: I read with interest the study by Moghaddam et al1 on the consanguinity and isolated atrial septal defect (ASD) in the North East of Iran. It is well known that congenital heart diseases (CHDs), particularly ASD, generally tend to follow multifactorial inheritance. However, autosomal dominant inheritance of ASD has been increasingly reported.2,3 This genetic form of inheritance together with the fact that consanguinity increases the risk of couples to have offspring with CHDs could result in the familial aggregation of ASD. It is expected for the familial aggregation of ASD to be prevailed in Iran. This is based on the following 3 points. (1) Among various types of CHDs, ASD has been reported to be predominant in Iran.4 (2) Consanguineous marriage is culturally preferable in Iran, and its trend has been noticed to be significantly on rise.5 (3) A total of 44% of ASD patients in the study by Moghaddam et al1 had parents with either the third-degree relationship or far relationship. Since associated cardiac, atrioventricular conduction, and skeletal anomalies are not uncommon in ASD, and in the view of potentially high occurrence of familial ASD in Iran based on the aforementioned 3 points, I presume that large-scale multicenter studies are needed to verify the requirement to screen ASD parents and their first-degree and second-degree relatives for associated anomalies.