Forms of central congenital hypothyroidism A) Isolated CH-C TSHβ-subunit TRHR B) CH-C caused by IGSF1 gene C) CH-C as part of MPHD1 I. Genes related to pituitary organogenesis 1. PROP1 2. POU1F1/PIT1 3. LHX3 4. LHX4 5. HESX1 II. Genes related to PSIS2 or isolated pituitary hypoplasia 1. SHH 2. TGIF 3. GLI2 1MPHD: Multiple Pituitary Hormone Deficiency 2PSIS: Pituitary stalk interruption syndrome

Table 1: Synopsis of genes related to central congenital hypothyroidism (CH-C).