A study involving nearly 6,000 African American older adults has found those with a specific gene variant have almost double the risk of developing late-onset Alzheimer’s disease compared with African Americans who lack the variant. The size of the effect is comparable to that of the ‘Alzheimer’s gene’, APOE-e4.
The gene (ABCA7) is involved in the production of cholesterol and lipids. It also affects the transport of several important proteins, including amyloid precursor protein, which is involved in the production of amyloid-beta.
The finding suggests that lipid metabolism may be a more important pathway in Alzheimer’s disease in African Americans than in whites. Cholesterol and lipid imbalances are more common in African Americans.
The gene does not seem to be a significant risk factor for whites, adding more weight to the idea that there are multiple pathways to the disease, and showing that the genetic underpinnings may vary among different populations (although it should be noted that other genes linked to Alzheimer’s risk in white populations were also significant for this group).
 . VAriants in the atp-binding cassette transporter (abca7), apolipoprotein e ϵ4,and the risk of late-onset alzheimer disease in african americans. JAMA [Internet]. 2013 ;309(14):1483 - 1492. Available from: http://dx.doi.org/10.1001/jama.2013.2973