There are two forms of FH. If you have inherited this genetic mutation from one parent, then you will have Heterozygous FH (HeFH). HeFH occurs in 1 in 250 people worldwide. If you inherit FH from both parents, it is much more severe in its consequences. This form of FH is called Homozygous FH (HoFH). It is very rare, occurring in about 1 in 160,000 to one million people worldwide.