This will be the youngest case of Alzheimer’s. A 19-year-old man in China has been diagnosed with Alzheimer’s disease. The diagnosis is difficult to establish, given the young age of the patient and the examinations carried out by the team following him. This case was described in the Journal of Alzheimer’s Diseases.
It all started with the fact that the patient, then a teenager, began to lose his memory and had difficulty concentrating. The symptoms increase until his ability to remember recent events (find things, know if he has eaten) and to read deteriorate. Because he had no family history or history of degenerative or mental illness, his case was transferred to a Beijing hospital.
Alzheimer’s disease ‘affects more than just the elderly’
Alzheimer’s disease appears in the vast majority of cases from the age of 65, but it is possible that the disease occurs earlier. According to France Alzheimer, about 33,000 people will develop the disease before the age of 65, and only 5,000 will be affected before the age of 60 in France. “This disease affects not only the oldest people. The so-called “young” outbreak usually occurs around the age of 40, which is always much older than this 19-year-old Chinese,” explains Professor Bruno Dubois. neurologist at the Pitié-Salpêtrière hospital in Paris, in science and the future. “Unlike the elderly, these young patients still have work or family responsibilities, which further complicates the situation.” Among cases occurring in people under 65, 10% are in people with rare hereditary familial forms of the disease, according to Inserm.
The case of a 19-year-old Chinese patient is difficult to analyze. The most important genetic risk factor known to date for the disease is the APOE4 gene. This multiplies by 15 the risk of developing the disease when the patient is a carrier of two alleles. It is also associated with an earlier onset of the disease. However, genetic tests have shown that the patient is not a carrier of this mutation, but of another variant of the APOE3 gene. On the other hand, the APP, PSEN1 and PSEN2 genes, all three associated with the formation of amyloid plaques, are associated with an inherited form of the disease with early onset. But these three genes are also missing from the DNA of a young Chinese man.
Search for amyloid plaques and tau protein
So what did the doctors use to diagnose this young man’s illness? First, on the WHO-UCLA AVLT Auditory Verbal Learning Benchmark, which assesses short-term and long-term memory. The results were abnormal, which confirms that he has many problems in this area. A diagnostic result that must be confirmed by additional results. First, MRI seeks to measure the volume of the hippocampus. “These areas are the earliest affected by Alzheimer’s disease. We are fortunate that we can accurately measure the reduction in the volume of these areas. We can really see atrophy in the patient’s pictures, which is certainly present, but at the very beginning. explains Professor Bruno Dubois. Similarly, FDG-PET, a test that shows which parts of the brain are consuming sugar and therefore functioning well, shows decreased activity in the temporal regions. “If a region consumes less sugar, we can conclude that it is affected. Knowing that Alzheimer’s often begins with damage to the temples, this result is consistent with the symptoms.”
Then the clinical examination of Alzheimer’s disease is based on two factors: a PET scan and an analysis of the cerebrospinal fluid. In both cases, doctors go looking for amyloid plaques, the accumulation of which prevents neurons from communicating with each other, as well as the presence of tau, the accumulated fibrillation of which leads to neurodegeneration. PET scan to see which molecules bind to amyloid plaquesshowed no lesions in the brain.
“During normal times, this type of test will eliminate the Alzheimer’s trail when it’s negative. Normally, the onset of lesions with amyloid plaques and tau protein precedes the onset of symptoms by about ten years in younger forms due to genetics. These are human carriers of mutations that we follow very far, even before the first signs appear, “comments Professor Dubois. Analysis cerebrospinal fluid showed the presence of tau “This is a marker of cerebral distress. However, this case needs to be seriously discussed and in the coming years it will be a matter of understanding why this patient does not have a lesion.” during control examinations.