Benchmark 6E
The Human Organism: Physical Health
Grades 9-12, page 146

Faulty genes can cause body parts or systems to work poorly. Some genetic diseases appear only when an individual has inherited a certain faulty gene from both parents.

NSES Content Standard C
Life Science: Structure and function in living systems
Grades 5-8, page 157
Disease is a breakdown in structures or functions of an organism. Some diseases are the result of intrinsic failures of the system. Others are the result of damage by infection by other organisms.