In the cells treated with TAR DNA binding protein (TDP-43) siRNA, wild-type POLDIP3 (variant-1) decreased and POLDIP3 lacking exon 3 (variant-2) increased. An increment of POLDIP3 variant-2 mRNA have been found in motor cortex, spinal cord and spinal motor neurons collected by laser capture microdissection with ALS. The gene discussed is TARDBP; the disease is amyotrophic lateral sclerosis.