Hyponatremia associated with trametinib monotherapy is potentially increased when combined with BRAF inhibitors.12 A study of endocrine effects of MEK and BRAF inhibitor therapy conducted in the same center to the present case, reported 16% (7/43) cases had hyponatremia during combined treatment with trametinib and a BRAF inhibitor (dabrafenib) and 13% (4/29) had hyponatremia with trametinib monotherapy.13 Three of these patients had CDI. The gene discussed is MAP2K7; the disease is Hyponatremia.