To examine if the high levels of genetic variation in CYP6ER1 in BPH field populations results, in part, from gene copy number variation (CNV), we resequenced the genomes of three BPH strains that primarily express CYP6ER1vA (NLF2), CYP6ER1vB (NLF7), or CYP6ER1vL (NLS), respectively. The gene discussed is C2CD4B; the disease is benign prostatic hyperplasia.