Histone demethylase that specifically demethylates both mono- and dimethylated 'Lys-9' of histone H3. May act as a transcription regulator controlling hair biology (via targeting of collagens), neural activity, and cell cycle. 2 2-oxoglutarate + N(6),N(6)-dimethyl-L-lysyl(9)-[histone H3] + 2 O2 = 2 CO2 + 2 formaldehyde + L-lysyl(9)-[histone H3] + 2 succinate Binds 1 Fe(2+) ion per subunit. Additional isoforms seem to exist. Strongest expression of isoforms 1 and 2 is seen in the small intestine, weaker expression in brain and colon, and trace expression is found in liver, pancreas, spleen, thymus, stomach, salivary gland, appendix and trachea. Isoform 1 is always the most abundant. Isoform 1 is exclusively expressed at low levels in kidney and testis. Isoform 2 is exclusively expressed at high levels in the skin. Contains two Leu-Xaa-Xaa-Leu-Leu (LXXLL) motifs. The LXXLL motifs are essential for the association with nuclear receptors (By similarity). The JmjC domain and the C6-type zinc-finger are required for the demethylation activity. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry.