The camp, held every two years, is being staged this weekend for the first time in Dunedin, at St Hilda's Collegiate School's Tolcarne boarding residence.
Mrs Paterson said life for families affected by Williams Syndrome was at times difficult due to its low prevalence.
Dunedin had four families with a Williams Syndrome child, but in some areas families were on their own.
The syndrome, first identified in 1961 by New Zealander Dr J. C. P. Williams, is a rare non-hereditary neurodevelopmental disorder caused by a deletion of about 26 genes from the long arm of chromosome seven.
It produces a distinctive "elfin" facial appearance, unusually cheerful demeanour and ease with strangers, variable developmental delay and cardiovascular problems.
Some people were able to work, while for many others, that was not possible.
Mrs Paterson said 123 people were attending the camp, including about 36 with Williams Syndrome, who ranged in age from 2 to over 50.
The camp was a mix of fun activities - including a helicopter ride and trips to Larnach Castle and Nature's Wonders - and speakers with a special interest in disability issues.
Syndrome sufferer Christina Crawford, of Auckland, said she loved coming to the camps and seeing friends. Mrs Crawford, who helped make a film about people with intellectual disabilities, said she worked to raise the profile and awareness of all intellectual disabilities, not just Williams Syndrome.
