Prader-Willi syndrome in New Zealand: a survey of 36 affected people.

The Prader-Willi syndrome consists of infantile hypotonia, failure to thrive, hypogonadism and developmental delay. It was first described in 1956. Later in life hypotonia improves. Between the age of two and four obesity becomes noticeable and between six and ten there is uncontrollable behaviour. A survey has been carried out of the 36 known cases in New Zealand and the pattern of the disease is similar to that elsewhere. In most cases the diagnosis was not established until between the ages of six and 10 when the obesity was marked and uncontrolled behaviour a problem. Early control of the obesity is helpful.