To provide a disease marker reflecting a bone dysbolism disease associated with the enhancement of the differentiation and activation of osteoclasts, a method for detecting the bone dysbolism disease by utilizing the disease marker and a method for screening a medicine useful for the improvement of the disease.

This polynucleotide having at least continued 15 bases and/or a polynucleotide complementary to it in a base sequence of a NF-ATc isoform a gene or Chloride intracellular channel 14 gene is utilized as the disease marker of the bone dysbolism disease associated with the enhancement of the differentiation and activation of the osteoclasts.