YY1 and congenital rubella syndrome: It is thus possible that polymorphisms in the RYBP gene may be implicated in CRS by dysregulating TP53 activity in TP53 or in its target genes via alteration of RYBP gene products or by altering binding at regulatory binding sites in the RYBP gene promotor area, which contains binding sites for the following transcription factors (YY1, IRF-1, C/EBPA, GATA-1, POU2F1).