The results indicated that C9orf72 repeat expansions were related to the risk of AD (OR = 6.36, 95% CI = 3.13–12.92, and p < 0.00001, Figure 1(a)) while C9orf72 intermediate repeat copies were not correlated with the risk of AD (OR = 1.04, 95% CI = 0.32–3.43, and p = 0.94, Figure 1(b)). Here, C9orf72 is linked to Alzheimer disease.