MYM-type zinc fingers were identified in MYM family proteins. Human protein ZMYM3 is involved in a chromosomal translocation and may be responsible for X-linked retardation in XQ13.1. ZMYM2 is also involved in disease. In myeloproliferative disorders it is fused to FGF receptor 1; in atypical myeloproliferative disorders it is rearranged. Members of the family generally are involved in development. This Zn-finger domain functions as a transcriptional trans-activator of late vaccinia viral genes, and orthologues are also found in all nucleocytoplasmic large DNA viruses, NCLDV. This domain is also found fused to the C termini of recombinases from certain prokaryotic transposons.