Bis-choline tetrathiomolybdate, or WTX101, is a salt of tetrathiomolybdate (TTM, MoS42−) and choline currently under investigation as a therapy against Wilson's disease, a rare and potentially fatal disease in which the body cannot regulate copper. Wilson disease is an autosomal recessive genetic disorder that is manifested by serious hepatic, neurologic or psychiatric symptoms. The disease is fatal if left undiagnosed and untreated. It is estimated that approximately 1 individual in every 15,000 worldwide have Wilson's disease, corresponding to approximately 30,000 individuals in the European Union and approximately 20,000 in the United States.