Based on a patient with a full deletion of IGSF1 clinically followed from neonate to adulthood, we investigated a common pituitary origin for hypothyroidism and macroorchidism, and the role of IGSF1 as regulator of pituitary hormone secretion.
Although IGSF1 loss has been noted in human hypothyroidism, this is the first reported phenotype in a family with copy number duplication in the region.