highly significantp = 1.85 × 10 −8
We extended this method to allow for the fact that many of our families had multiple affected offspring (see supplementary methods ) and found that the imprinting-only model was preferred ( supplementary table 4 ); under that model, the imprinting effect was highly significant ( p = 1.85 × 10 −8 ) with the ratio of allelic effects for paternally to maternally inherited alleles equal to 0.75.