This is a nice case of prolactin resistance due to loss-of-function variant in the prolactin receptor (PRL-R) gene. A 35 year old female with hyperprolactinemia became pregnant twice, but was unable to lactate. It would take some time before the PRL-R genetic testing becomes available in clinical practice. Nonetheless, the case expands our knowledge of prolactin pathogenesis.
N E J M
A loss-of-function variant in the gene encoding the prolactin receptor (PRL-R) 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 PRL-R. Her unaffected parents are heterozygotes. These findings are consistent with previous work showing that mice deficient in functional Prlr do not lactate.