Age is the primary risk factor for the condition, which is why this most recent example is so unique.
According to a recent case report published in the Journal of Alzheimer’s Disease, a 19-year-old Chinese man who has been experiencing memory issues since he was 17 was identified as having dementia. The teenager was identified as having “probable” Alzheimer’s disease by doctors at the Capital Medical University in Beijing after a battery of tests. If the diagnosis is accurate, he will be the youngest person ever known to have the debilitating condition.
Age is the primary risk factor for the condition, which is why this most recent example is so unique.
Although the precise causes of Alzheimer’s are still largely unknown, the accumulation of the proteins beta-amyloid and tau in the brain is a well-known symptom of the condition.
Youngest dementia patient
Beta-amyloid is typically present in high concentrations outside of neurons (brain cells) in Alzheimer‘s patients, whereas tau “tangles” are present inside axons, the long, slender projections of neurons. The 19-year brain did not exhibit any indication of these characteristics, despite scans. However, the p-tau181 protein was detected in abnormally high concentrations in the patient’s cerebral fluid by the researchers. This frequently occurs prior to the development of tau tangles in the brain.
Alzheimer’s disease affects nearly all individuals under the age of 30 and is caused by inherited defective genes. In fact, the 21-year-old, who was the previous youngest example, had a hereditary cause.
The three genes amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 have been related to the development of Alzheimer’s disease in children (PSEN2).
These genes play a role in the synthesis of beta-amyloid peptide, a protein fragment that is a precursor to the previously mentioned beta-amyloid.
An aberrant buildup of beta-amyloid (plaques) in the brain, a defining feature of Alzheimer’s disease and a target for treatments like the recently approved medicine lecanemab, can result from a defective gene.
To have Alzheimer’s disease, a person just needs one of the genes APP, PSEN1, or PSEN2 to be defective, and their children have a 50:50 chance of inheriting the gene from them and getting the condition as well.
A genetic reason, however, was ruled out in this most recent case since whole-genome sequencing of the patient revealed no known genetic abnormalities.
Also, there is no family history of dementia or Alzheimer’s disease in the teen’s family.
The young man was free of any further illnesses, infections, or head injuries that would have contributed to his condition.
It is obvious that he has a very uncommon form of Alzheimer’s, whichever one it may be.
Memory impairment in the young patient
The patient first experienced difficulties focusing on his academic work when he was 17 years old. A year later, he started to lose his short-term memory. He had no recollection of having eaten or completed his schoolwork. He had to leave high school because his memory loss got so bad (he was in his final year).
Standard cognitive testing to look for memory loss revealed a possible diagnosis of Alzheimer’s disease.
The findings indicated that his memory was substantially compromised. His hippocampus, a region of the brain important in memory, has also shrunk, according to the brain scans. This is a common precursor to dementia.
Understanding the biological causes of his dementia is challenging; as a result, this case is still a medical mystery. A brain biopsy would be too hazardous.
Alzheimer’s disease with early onset is becoming more common in younger individuals. Sadly, we won’t likely hear of another uncommon case like this one very soon.
Parvathy Sukumaran 
