PROP1 and hypopituitarism: 2) The prevalence rate of breech delivery was significantly higher in the PSIS-CPHD subgroup [combined pituitary hormone deficiency (CPHD) patients diagnosed with PSIS] than in the POU1F1/PROP1-CPHD subgroup (CPHD patients carrying POU1F1/PROP1 pathogenic mutations) (44.4% vs 5.5%, P=0.004) (55).