Possible causes of CYP21A1P/CYP21A2 formation are associated with 1) high recombination rate in the MHC locus, 2) high recombination rate between highly homologous genes and pseudogenes in the CYP21 gene area, and 3) the existence of chi-like sequences and repetitive minisatellite consensus sequences in CYP21A2 and CYP21A1P which play a role in promoting genetic recombination..     ///    Chimeric CYP21A1P/CYP21A2 genes were present in 171 out of 508 mutated CYP21A2 alleles (33.8%).     ///    Chimeric CYP21A1P/CYP21A2 genes identified in Czech patients with congenital adrenal hyperplasia..     ///    "In this study, we describe chimeric CYP21A1P/CYP21A2 genes detected in our patients with 21-hydroxylase deficiency (21OHD). "    ///    "We detected four types of chimeric CYP21A1P/CYP21A2 genes: three of them have been described previously as CH-1, CH-3, CH-4, and one type is novel. "