What are the chances of having more then one child with hypoplastic left heart syndrome?

2-6% with 1-2 sibs: Multifactorial inheritance usually is quoted for hlhs, with a 2% recurrence risk if one prior affected sibling and a 6% recurrence risk with two prior affected siblings. Rarely an autosomal recessive form can be seen with 25% recurrence risk from the same parents.

Tiny: The genetic influences on heart formation/defects are complex and located on several separate chromosomes.The risk of you having another kid with ANY heart defect (there are lots of them) is about 4%, while that of the same defect is incredibly small.