Correct, they all share a genetic disorder called Marfan's Syndrome. This is not a disease, but a disorder of connective issue that manifests as long spindly limbs, sleek elongated face and nose, flat feet, overcrowded mouth with teeth, flexible joints and long spindly fingers. For example, Michael Phelps is 6' 4" tall but his arm span is 6' 7"!
Paganini, the virtuoso violinist born Genoa in 1782 had long spindly fingers and the first joint of each finger was double jointed enablung him to bend it with ease to another string in extremely rapid succession. Not surprisingly, the music he composed to show off his dexterity and virtuosity was deemed impossible to play by other virtuossi of the time and people rumoured he had made a pact with the devil to be able to play such challenging music. He could play 3 octaves easily of the violin's 3.5 octave range.
Tutankhamun died young but his remains showed scolios (abnormal curvature of the spine) and other features of Marfan's.
Sergei Rachmaninov the russian composer and pianist also suffered from Marfan's Syndrome that gave him a a huge span of his hands. he could span 11 notes on the piano with each hand - the opening chords of his Piano Concerto #2 in C sharp Minor exploited his span and made it very challenging for other Concert Pianists to play at that time.
Abraham Lincoln had Marfan's. There are others with the condition.
The most serious complications of Marfan's involve the heart and aorta with an increased risk of mitral valve disease and aortic aneurysm. Other commonly affected areas include the lungs, eyes, bones and the covering of the spinal cord. It is an inherited condition.
If you want to see pictures of people with Marfan's:
https://www.flickr.com/photos/nationalmarfanfoundation/sets/72157612643340384/
JonW has the answer so his turn to set the question.