This is confirmed by Tamura et al., where raised ADH levels of 5.8 pg/mL (normal: 0.3–3.5 pg/mL) in the background of normal CT thorax and CT/MRI brain (no pulmonary or pituitary lesions) and normal thyroid function test and adrenal function tests, elucidating the mechanism of SIADH from ectopic production by small-cell GBC [9]. The gene discussed is AVP; the disease is inappropriate ADH syndrome.