In 2023, neurologists at a memory clinic in China diagnosed a 19-year-old with what they believed to be Alzheimer's disease – making him the youngest person ever to be diagnosed with the condition.The teen first began experiencing memory decline around age 17, with symptoms worsening over time.Brain scans revealed shrinkage in the hippocampus, a region involved in memory, while his cerebrospinal fluid showed biomarkers consistent with Alzheimer's – the most common form of dementia.Although usua...