PROBLEM TO BE SOLVED: To provide a TDP-43 variant having agglomerate forming ability and cytotoxicity in the whole length sequence； and a screening method of a compound for therapy and/or prevention of TDP-43 agglomerate-accumulating diseases by utilizing the TDP-43 variant.SOLUTION: A TDP-43 variant comprises an amino acid sequence with a cysteine at the 173 and/or 175 positions being substituted in TDP-43 amino acid sequence. A screening method of a compound for therapy and/or prevention of TDP-43 agglomerate-accumulating diseases comprises the following steps of: (1) bringing the TDP-43 variant into contact with a compound as a candidate； (2) detecting agglomerate formation inhibitory activity of the compound； and (3) selecting a compound inhibiting agglomerate formation.
