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Men who have FH may have heart attacks in their 40s to 50s, and 85% of men with the disorder have a heart attack by age 60. Affected women may have heart attacks in their 50s and 60s.
Individuals with the rare, autosomal recessive form of FH (also called homozygous FH) develop xanthomas beneath the skin over their elbows, knees and buttocks as well as in the tendons at a very early age, sometime in infancy. In individuals with this form of FH, heart attacks and/or death may occur before age 30, sometimes in young children if they are not aggressively treated.
Familial hypercholesterolemia is caused by mutations in the LDLR gene which is located on chromosome 19. The defect makes the body unable to remove LDL cholesterol from the bloodstream. This results in consistently high levels of LDL in the blood, which leads to atherosclerosis at an early age as well as deposits of cholesterol in other tissues like the skin and tendons.