Because of the previous findings that autoantibodies against TRPM1 were found in the serum of patients with MAR, the sera of the three MAR patients (MAR1-3) reported herein were tested on COS-7 cells overexpressing the different isoforms of human TRPM1 (70+TRPM1, 92+TRPM1 and 109+TRPM1). Here, TRPM1 is linked to myelodysplastic syndrome associated with isolated del(5q).