Scientists Discover Two Rare Genes Linked to Alzheimer's

A study published in JAMA Network Open identified two rare genetic variants linked with Alzheimer's, reports Newsweek . The researchers analyzed the DNA sequences of 5,617 people with Alzheimer's, and those of 4,594 controls. The variants identified in two participants with cognitive impairments included a mutation in the NOTCH3 gene, which has previously been associated with cerebral autosomaldominant arteriopathy with subcortical infarcts and leukoencephalopathy. People with this condition suffer severe headaches and strokes in early adulthood, before developing vascular dementia generally between 40 and 55. Four subjects exhibited the TREM2 mutation called Q33X, which is believed to trigger Nasu-Hakola disease, a type of early-onset dementia that induces cysts that often cause fractures. "This dementia occurs when a person has a double dose of this particular mutation, whereas the Alzheimer cases we identified had only a single dose," noted the Boston University School of Medicine's Lindsay Farmer. The authors noted that "different mutations in the same gene or variable dose of a mutation may be associated with result in distinct dementias. These findings suggest that minor differences in the structure or amount of protein may be associated with different clinical outcomes."