Two families, two pathways: a case series of 46, XY DSD with 17α-hydroxylase deficiency and isolated 17,20-lyase deficiency due to novel <i>CYB5A</i> variant

Here, we report four patients with 46, XY disorder of sexual development (DSD) from two families with 17α-hydroxylase deficiency and isolated 17,20-lyase deficiency due to cytochrome b5 variant with a variable spectrum of under-virilization who had received inadequate treatment for a prolonged period of time due to incorrect diagnosis.