The 16-year-old has Coffin-Lowry syndrome which impacts 1 in 40,000-50,000 people and has affected her intellectual abilities.
Her cognitive thinking is impacted by the rare genetic disorder, Dover said, which makes her more like a child than a teenager.
Police have been notified of her disappearance and are helping the family in trying to locate her, searching the property she had previously been found at twice.
Dover said the family have been searching all over the internet, as well as attending a boy racing meet in Hamilton over the weekend to pass her picture around.
Sky could potentially be found anywhere in the country but her family say she has contacts in Dargaville, Tauranga, Tokoroa, Huntly, and Hamilton.
The teenager's family and police both have concerns over her safety and are asking for anyone with information to come forward.
"She was last seen at home on the evening of Wednesday, January 16, wearing a dark hoodie, denim skirt and red shoes," a police spokesperson said.
"Anyone who has seen Sky is asked to call Police on 07 577 4300."