These children often present when they fail to enter puberty, or later with infertility. The incidence is around 1 in 500 - 1000 live births. They are often tall with long limbs, slightly below normal intelligence. The risk increases with maternal age because it is due to non-disjunction of the maternal X chromosome. However this should regress as testosterone levels increase.
Most Doctors underestimate what children can do though.
Whilst most 3 year olds can copy a circle, a square is a 4 year fine-motor milestone. Hopping is really quite advanced, and is a 4-5 year milestone. We think this is a clever question. The condition persists for about 48 hours and then subsides. A rapid fall in sodium is more likely to cause convulsions.