Levene died in 1940, before the true significance of DNA became clear. Levene is known for his tetranucleotide hypothesis (formulated around 1910) which first proposed that DNA was made up of equal amounts of adenine, guanine, cytosine, and thymine.
Alzheimer's is not just a disease of old age. Younger-onset (also known as early-onset) Alzheimer's affects people younger than age 65.Up to 5 percent of the more than 5 million Americans with Alzheimerâs have younger-onset.eople who have early onset Alzheimer's may be in any stage of dementia â early stage, middle stage or late stage. The disease affects each person differently and symptoms will vary. If you are experiencing memory problems: 1  Have a comprehensive medical evaluation with a doctor who specializes in Alzheimer's disease.
Early-onset Alzheimer's disease is diagnosed before age 65. The news is usually shocking, and it means you need to plan now for big changes ahead, so you'll be safe and get the care you need as time goes on. The early-onset form most often shows up when you're in your 40s and 50s. But it's not unheard of for people to get it as young as their 30s. Because Alzheimer's robs you of your memory, your ability to think clearly, and ultimately to take care of yourself, you'll need a strong support system.