IGSF1 abnormality causes diverse symptoms, including congenital central hypothyroidism (CCH), prolactin hyposecretion, testicular enlargement and delayed puberty.
Recent reports have indicated that loss-of-function mutations in the immunoglobulin superfamily member 1 gene (IGSF1, OMIM 300888) cause congenital central hypothyroidism with macroorchidism.
Our findings provide additional genetic evidence that loss-of-function mutations in IGSF1 cause an X-linked form of C-CH and variable prolactin deficiency.