Table 2. Differential diagnosis point of FH and familial combined hyperlipidemia (FCHL).

	FH Heterozygotes	FCHL
Gene	Monogenic causes LDL receptor (LDLR) Apolipoprotein B-100 (APOB) Proprotein convertase subtilisin-like kexin type 9 (PCSK9) LDLR adaptor protein 1 (LDLRAP1)	Complex genetic causes Upstream transcription factor 1 (USF-1), Lipoprotein lipase (LPL), etc.
Prevalence	1 in 200 -500	1 in almost 100
lipid profile	Mostly type IIa, often type IIb	In family and individual, variable phenotype of type IIa and/or type IIb and/or type IV
Tendon and skin xanthomas	Often observed	Not observed
Premature corneal limbus	Often observed	Not usually observed
Small dense LDL	Rare	Characteristic feature of FCHL
Insulin resistance	Rare	Often observed