Other way around
About 1/3 of ds patients will have a heart
defect including many with a vsd or other more complex defects.
However, of all those with vsd the ds group is only a fraction of the larger number. Vsd's are relatively common & represent a failure in completion of the walls between the chambers that grow out from the side & knit together during fetal life. >1/2 will close on there own by a year of age.