PLOD1 and autosomal erythropoietic protoporphyria: Another interesting finding was that the FMV total U-LH concentrations were not only above the aforementioned cut-off value of 0.3 IU/L in all the five LPP girls differentiating them from all the five EPP girls, but also at or above 0.6 IU/L in four of the five LPP girls, two of whom were even younger than some of the EPP girls.