What type of disease is caused by a defect in a gene?

A disease caused by a defect in a gene is classified as hereditary. This type of disease is inherited from one or both parents due to specific genetic mutations or abnormalities that affect how cells function. Hereditary diseases can include various conditions, such as cystic fibrosis, sickle cell anemia, and Huntington's disease, each resulting from genetic material passed down through family lines.

Familial conditions may present in families but do not necessarily stem from a single gene defect; they can also arise from multiple genes interacting with environmental factors. Iatrogenic diseases are those caused by medical treatment or intervention, while congenital diseases are present at birth, which may or may not be hereditary. Thus, the classification of hereditary accurately reflects conditions caused specifically by genetic defects, providing clarity in genetics and family health patterns.