Variant prolactin receptor in agalactia and hyperprolactinemia

A loss-of-function variant in the gene encoding the prolactin receptor (PRLR) was reported previously in a woman with persistent postpartum galactorrhea; however, this paradoxical phenotype is not completely understood. Here we describe a 35-year-old woman who presented with idiopathic hyperprolactinemia that was associated with a complete lack of lactation after each of her two deliveries. She is a compound heterozygote for loss-of-function variants of PRLR. Her unaffected parents are heterozygotes. These findings are consistent with previous work showing that mice deficient in functional Prlr do not lactate.