Personalized RN Registered Nutcase Youth T-Shirt. RN registered nutcase is a funny twist on the acronym for registered nurse and a unique gift design for birthdays, holidays and graduation. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.