Single studies have reported that carriers of the A allele of the TNF-α 308 G/A gene were variably associated with increased risk of Alzheimer’s disease (207–210) and that carriage the higher IL-6 producing allele of IL-6 (174 G/C) may confer increased risk (186, 190, 191). Here, IL6 is linked to early-onset autosomal dominant Alzheimer disease.