Is pendred syndrome 100% heredity? could someone without pendred syndrome history in family will have a chance to have it?

Recessive disorder: Pendred's syndrome is inherited in an autosomal recessive manner. This means that both parents must transfer a copy of the defective gene to the child in order for the disease to occur. If both parents are carriers of the trait, the child has a 1:4 chance of being affected. An important aspect of genetic disorders is penetrance- how will people with the genetic make up be affected.

Yes : Pendred syndrome is a genetic disorder with what is known as autosomal recessive inheritance. In order to have the disease a person needs to inherit an abnormal gene from each parent. Good information on the disorder can be found at https://www.Nidcd.Nih.Gov/health/hearing/pages/pendred.Aspx.