The function of FAM220A (family with sequence similarity 220 member A, ENSG00000178397) is as follows. Promotes dephosphorylation of transcriptional activator STAT3 by interacting with both STAT3 and protein phosphatase PTPN2. This promotes interaction of PTPN2 with STAT3 and mediates STAT3 dephosphorylation by PTPN2, leading to negative regulation of STAT3 transcriptional activator activity. May be required for spermiogenesis or sperm function. .