The Tanzanian government's system of rounding up children with albinism in state-run education centers isn't adequately protecting them from widespread superstitious beliefs that human albino body parts will bring wealth and success or cure disease, the U.N. human rights office said Monday.

People with the genetic condition, characterized by a lack of pigment, are often referred to in Tanzania as ghosts, or zero zero, which in Swahili signifies someone who is less than human. Witch doctors often lead brutal attacks to use albino body parts in potions they claim bring riches.

The government started placing children and adults with the snow white skin, blond hair, and blue eyes into education centers after a wave of attacks started six to eight years ago and caught the attention of Western journalists.

The United Nations is now examining whether some of the 23 known education centers in Tanzania are engaging in segregation by forcibly removing from their homes hundreds of children with albinism who are at risk of being killed, mutilated or sexually abused, said human rights officer Alicia Londono.

"There is an increased concern that what has been a temporary emergency measure that was welcome at the beginning of the wave of attacks has really become a long-term solution and conditions in the centers are appalling," said Londono after a visit to the area earlier this month.

She said the policy cuts children off from all contact with their families and allows the overcrowded centers to be used as a "dumping ground," where children are exposed to the risk of sexual abuse and harsh physical punishment.

Her office says it has documented 151 attacks on people with albinism, about half of them murders, in Tanzania since 2000. She said a new wave of brutal attacks last year prompted renewed attention to the problem.

One out of every 1,400 citizens in Tanzania has albinism. By comparison, the global average is about one in 20,000 people, according to Canada-based albinism advocacy group Under the Same Sun.