This syndrome has been made popular by Rebeecca Black's "Friday" song.
The syndrome has been relatively ignored until this point. This has been a condition that effects all ages and races. Some of the signs of My-hand-is-a-Dolphin Syndrome (a.k.a. MHISADS) is the need to roll down the window in the car when you are "kicking it" in the front-seat or in the back-seat with your friends, then sliding your arm out and moving your hand and forearm up and down in a fashion which appears like a dolphin riding a bow of a ship.
Ryan - "Yeah, i was taking Nick home and all of a sudden, he started moving his hand up and down out the window like a damn dolphin"
Kevin - "Wow! I guess he caught that My-hand-is-a-Dolphin Syndrome. That's crazy! Hope you don't get it"