recurrence risk

When a genetic condition has appeared in a family, the natural next question is: could it happen again? Recurrence risk is the probability that the same condition will show up in another child or relative. It turns a worry into a number a family can actually reason with.

For straightforward single-gene conditions the figure often follows clear inheritance rules: a one-in-four chance for many recessive disorders when both parents are carriers, or one-in-two for many dominant ones. For chromosomal and complex multifactorial conditions, estimates rely on empirical data drawn from studying many similar families.

Honest counseling stresses that these are probabilities, not predictions for any single pregnancy — a 25% risk does not mean one affected child in every four, but a chance that applies independently each time. Factors like parental mosaicism or new mutations can also shift the true figure.