Swedish scientists discover aggressive, early onset Alzheimer’s in 40-year-olds
A team led by neurobiologists in Sweden have discovered a rare and aggressive form of Alzheimer’s unique to a family in Uppsala: the gene mutation, or Uppsala APP deletion, is behind rapid deterioration of cognitive function and invariably causes descent into dementia at a younger age than usual –symptoms begin in the early 40s.
Alzheimer’s is a notorious mind-robbing disease that that wipes out memories and destroys one’s sense of self. Most cases of arise sporadically after the age of 65; early onset Alzheimer’s, before the age 65.
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“Affected individuals have an age at symptom onset in their early forties, and suffer from a rapidly progressing disease course,” asserted Dr. María Pagnon de la Vega, from the Department of Public Health and Caring Sciences at Uppsala University in Sweden.
Dr. Pagnon de la Vega collaborated with a large team of scientists throughout Europe to study an extraordinarily rare form of the disease that so far has been found only in one family. The Uppsala APP deletion, as it became known is a deletion in a specific string of amino acids that are part of the amyloid precursor protein. It affects the brain tissue of mutation carriers.
Picture a pearl necklace made significantly shorter, the result of six missing beads.
The amino acids “beads” are not in the strand because the APP gene in this Swedish family doesn’t code for them. In terms of numbers, the deletion cuts out a swath of six amino acids, resulting in destructive deposits of protein plaques throughout the brain.The gooey plaques destroy neurons and, as a result, annihilate the executive functions of the brain itself, such as working memory, mental flexibility, and self-control.
Brain scans of two siblings and a cousin in this Swedish family revealed evidence of atrophy, or diseased tissue, in similar regions of the brain. Scores on Mini Mental State Examination, an assessment frequently administered to the elderly to test cognitive skills, were not only low but in a range usually seen in cognitively impaired older adults. All were still in their early 40s at the time.
[At the time of assessment, the two siblings and cousin were all seriously symptomatic. They were having trouble speaking and had lost the ability to perform simple math.]
According to Dr. Pagnon de la Vega and colleagues, this form of Alzheimer’s disease is defined as autosomal dominant, passed from one generation to the next, and moving rapidly on a downhill course. There is no data suggesting other families carry the Uppsala APP deletion, although other forms of familial Alzheimer’s have been identified in Sweden.
The Uppsala APP deletion is the first multiple amino acid deletion that leads to early onset Alzheimer’s.
Alzheimer’s disease, whether sporadic or genetic, has no cure and is responsible for US$355 billion in total costs each year in the U.S. alone, data from the Alzheimer’s Association in Chicago, show.
