NOTE: A person may be designated as homozygous FH and not be homozygous (if compound heterozygous, if LDL-C is sufficiently high, or if autosomal recessive).
LDL-cholesterol raising genetic defects include:
(1) mutations in LDL-receptor
(2) mutations in apolipoprotein B
(3) mutations in PCSK9
Clinical criteria for homozygous familial hypercholesterolemia - both of the following:
(1) LDL-cholesterol >= 400 mg/dL
(2):one or both parents have one of the following:
(2a) clinically diagnosed with familial hypercholesterolemia
(2b) positive for an LDL-C raising mutation
(2c) have autosomal recessive familial hypercholesterolemia
Genetic criteria - one of the following:
(1) two identical LDL-cholesterol raising genetic defects (true homozygous)
(2) two nonidentical (compound heterozygous) LDL-cholesterol raising genetic defects
(3) autosomal recessive familial hypercholesterolemia
If a patient has 1 abnormal LDL-C raising genetic defect AND a serum LDL-C > 400 mg/dL, then the patient is treated as a homozygous.
A patient may be homozygous for an LDL-cholesterol raising mutations AND have an LDL-C < 400 mg/dL.
