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.
Alzheimerâs disease is usually thought of as something senior citizens get. While that is often true, itâs not always the case: Up to 5% of people diagnosed with Alzheimerâs are under age 65âusually in their 40s or 50sâand are considered to have an âearly onsetâ or âyounger onsetâ of the disease.irst things first: Early-onset Alzheimerâs disease is uncommon, and itâs not responsible for most cases of middle-aged forgetfulnessâlike not being able to remember where you put your keys, or the name of someone you met at a cocktail party last night, for example.