Mosaic individuals are usually exceptionally tall, have above average intelligence and are always sterile. This is a X linked disorder. Stills - Children with Stills are normal at birth. As the child gets older, they slowly lose control of the skeletal muscles. They lose the ability to walk, then the ability to use their hands and arms, and finally the ability to talk.
Most Stills die in their twenties but a few survive into their forties with extensive medical care.
Stills have a normal intelligence level and are always females. Females with Stills carry the trait on both X chromosomes. Females that carry the Stills trait on just one X chromosome seem to be normal. Our geneticists suspect male embryos carrying the Stills trait do not develop. Alligator - Children with Alligator's disease look normal when born, but soon develop dry, scaly skin.