The case has highlighted the shame felt by families who have children with disabilities in Palestinian society "made worse because of poor services and the practice of first-cousin marriages in Arab communities."
"This is sad, shameful and awful," The Scotsman quoted Imad Abumohr, a disabled rights activist, as saying.
Few people in the rural town of Beit Awwa knew of Basam Musalmeh, 38, and his sister Nawal, 42 were kept in two crumbling concrete rooms that stank of sweat and urine behind their family's house.
Police found them during a raid on Tuesday night, while searching for Hamas loyalists and criminals in the village.
Palestinian police commander Samih Saify said that during the search police heard unusual noises and went to investigate. He said they found Basam Musalemeh naked, while Nawal wore a flimsy nightdress.
Their father was arrested, although it was not clear if he was detained for keeping his children locked up or because of his suspected loyalty to militant group Hamas.