Familial Hypercholesterolemia

Familial hypercholesterolemia (Decreased LDL receptor signaling)

Clinical Presentation: Achilles tendon xanthoma

Autosomal Dominant Diseases (Page 56)

Familial Dyslipidemias (Page 90) 
Type II - Familial hypercholesterolemia; Inheritance: AD; Pathogenesis: Absent or defective LDL receptors  
High Blood Level: IIa: LDL, cholesterol IIb: LDL, cholesterol,VLDL  
Clinical: Heterozygotes (1:500) have cholesterol ≈ 300mg/dL; homozygotes (very rare) have cholesterol ≈ 700+ mg/dL. Accelerated atherosclerosis (may have MI before age 20), tendon (Achilles) xanthomas, and corneal arcus.

Hyperlipidemia Signs (Page 291) 
Tendinous xanthoma: Lipid deposit in tendon, especially Achilles.