A study of the Han population showed that the genotype and allele frequency of IGF-1 rs972936 were significantly different between Alzheimer's disease cases and healthy controls (Pgenotype P = 0.006, Pallele P = 0.047), and compared with C alleles, people carrying the T allele of rs972936 are 1.16 times more likely to develop Alzheimer's disease [36]. Here, IGF1 is linked to early-onset autosomal dominant Alzheimer disease.