Familial Hypercholesterolemia (AD, LDLR)

A 38-year-old man presents with his first myocardial infarction. Clinical examination reveals tendon xanthomas over the Achilles tendons and extensor surfaces of the hands, and corneal arcus noted at age 30. Serum LDL cholesterol is 290 mg/dL despite no prior lipid-lowering therapy. His pedigree (shown in the diagram) demonstrates **A**: affected individuals in every generation, approximately 50% of offspring affected, male-to-male transmission, and equal involvement of both sexes. His 12-year-old daughter has LDL 260 mg/dL, and his 8-year-old son has LDL 240 mg/dL. Genetic testing confirms a heterozygous pathogenic mutation in the LDLR gene on chromosome 19p13.2. Which inheritance pattern does the pedigree marked **A** demonstrate?