It is reported in literature [29, 30] that, COL4A3/A4 mutations in cis resemble an AD inheritance with a more severe phenotype, while COL4A3/A4 mutations in trans mimicks an autosomal recessive inheritance with a less severe phenotype, and COL4A5 combined with COL4A3 triggers a more severe phenotype. Here, COL4A3 is linked to Alzheimer disease.