Yes, there is a difference in Alzheimer’s risk between familial and common Alzheimer’s cases. Familial Alzheimer’s disease (FAD) refers to cases where there is a clear inheritance pattern within families, typically caused by mutations in specific genes such as PSEN1, PSEN2, or APP. FAD accounts for a small proportion of Alzheimer’s cases (less than 5%).
In contrast, sporadic or common Alzheimer’s disease occurs in individuals without a clear family history and is the most common form of the disease. Common Alzheimer’s cases have a more complex etiology, involving a combination of genetic, environmental, and lifestyle factors. The APOE gene, particularly the APOE4 variant, is the most prominent genetic risk factor for common Alzheimer’s disease. However, having the APOE4 variant does not guarantee the development of the disease, and many individuals with common Alzheimer’s do not have a known genetic mutation.
The distinction between familial and common Alzheimer’s helps researchers understand different underlying mechanisms and has implications for genetic testing, counseling, and potential treatment approaches.