Table 6

Familial Hypercholesterolemia Diagnostic Categories

ICD-10 CategoryClinical CriteriaWith Genetic Testing Performed
Heterozygous FHLDL-C ≥160 mg/dL (4 mmol/L) for children and ≥190 mg/dL (5 mmol/L) for adults and with 1 first-degree relative similarly affected or with premature CAD or with positive genetic testing for a LDL-C raising gene defect (LDL receptor, apoB, or PCSK9)Presence of 1 abnormal LDL-C raising gene defect (LDL receptor, apoB, or PCSK9)
Diagnosed as heterozygous FH if LDL-C raising defect positive and LDL-C <160 mg/dL (4 mmol/L)
Occasionally, heterozygotes will have LDL-C >400 mg/dL (10 mmol/L); they should be treated similarly to homozygotes
Presence of both abnormal LDL-C raising gene defects (LDL receptor, apoB, or PCSK9) and LDL-C lowering gene variant(s) with LDL-C <160 mg/dL (4 mmol/L)
Homozygous FHLDL-C ≥400 mg/dL (10 mmol/L) and 1 or both parents having clinically diagnosed FH, positive genetic testing for a LDL-C raising gene defect (LDL receptor, apoB, or PCSK9) or autosomal-recessive FH
If LDL-C >560 mg/dL (14 mmol/L) or LDL-C >400 mg/dL (10 mmol/L) with aortic valve disease or xanthomata at <20 years of age, homozygous FH highly likely
Presence of 2 identical (true homozygous FH) or nonidentical (compound heterozygous FH) abnormal LDL raising gene defects (LDL receptor, apoB, or PCSK9); includes the rare autosomal-recessive type
Occasionally, homozygotes will have LDL-C <400 mg/dL (10 mmol/L)
Family history of FHLDL-C level not a criterion; presence of a first-degree relative with confirmed FHGenetic testing not performed

Reprinted with permission from Gidding, et al. (39).

apoB indicates apolipoprotein B; CAD, coronary artery disease; FH, familial hypercholesterolemia; ICD-10, International Classification of Disease, 10th Revision; LDL, low-density lipoprotein; LDL-C, low-density lipoprotein cholesterol; and PCSK9, proprotein convertase subtilisin/kexin 9.