NOTCH3 and Alzheimer disease: Analysis of mitochondrial DNA variants revealed that most individuals in this cluster had mitochondrial haplogroups K1a1b1a or K1a9 that are common among Ashkenazi Jewish individuals.22 Moreover, NOTCH3 mutations carriers accounted for 4.0% of the participants with AD who have either the K1a1b1a or K1a9 haplogroup.