The great white shark is very well known for its size, with the  largest individuals known to have approached or exceeded 6 metres  (20 ft) in length and 2,268 kilograms (5,000 lb) in weight. It  reaches maturity at around 15 years of age and can have a life span  of over 30 years.
Benign fasciculation syndrome is characterized by occasional or nearly continuous twitching of various skeletal (voluntary) muscles in the body. This type of muscle twitching can also be seen in association with serious disorders like spinal injury, multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS).
Scientists also don't know for certain what causes ALS (aka Lou Gehrig's disease) in general and are studying genetic and environmental links, the CDC notes. But although the underlying reasons for Hawking's long-term survival are unclear, researchers' thoughts on it aren't. He is exceptional, neurology professor Nigel Leigh told the British Medical Journal in 2002. I am not aware of anyone else who has survived with [ALS] as long.. What also makes Hawking's case unusual is that he was informed of his illness so young: The average age for diagnosis is 55, the Post notes, though Hawking's early onset may have helped him in the long run.