NEW YORK (Thomson Reuters Foundation) - Shy, soft-spoken Mwigulu Magesa, missing an arm from a brutal attack in Tanzania where albinos are targeted for their body parts, wants to be president some day and knows exactly what he will do when he takes office.

"If someone does such a thing like chopping a body part of a person with albinism or killing a person with albinism, he is sentenced to death the same day," the 12-year-old boy said in Swahili through an interpreter.

"By hanging them," he added in a stronger voice.

For now, Mwigulu's days are filled with more cheery thoughts as he and three other Tanzanian children wrap up a summer in New York being fitted with prosthetic limbs and learning the simple childhood joys of splashing in a pool and playing backyard soccer.

But in the next few days Mwigulu, along with Pendo Noni, 15, Emmanuel Rutema, 13, and 5-year-old Baraka Lusambo will return to Tanzania, where people with albinism live in danger.

Albino body parts are highly valued in witchcraft and can fetch a high price. Superstition leads many to believe albino children are ghosts who bring bad luck.

Some believe the limbs are more potent if the victims scream during amputation, according to a 2013 United Nations report.

Albinism is a congenital disorder affecting about one in 20,000 people worldwide who lack pigment in their skin, hair and eyes. It is more common in sub-Saharan Africa and affects about one Tanzanian in 1,400.

United Nations officials estimate about 75 albinos have been killed in the east African nation since 2000 and have voiced fears of rising attacks ahead of this year's election, as politicians seek good luck charms from witch doctors.

The government has banned witch doctors to stop the body parts trade but when these children go home, they face a future that can be bleak.

They may attend schools deemed "safe" but may live in one of a handful of government centers plagued by overcrowding, food shortages and little opportunity to work, said Ester Rwela, a social worker with Under the Same Sun, a charity that advocates for people with albinism.

The Canada-based charity works to provide protection, support and education for people with albinism.

Rwela accompanied the children to New York, where they have been cared for by Elissa Montanti, founder of the Global Medical Relief Fund which aids children injured in disaster or conflict.

The Fund has helped nearly 200 severely injured children and, while she has bid sad farewells to them all, the little ones from Tanzania have really touched her, she said.

"War is one thing, stepping on a land mine is one thing," Montanti said. "But this is so deliberate. It is one human to another, causing such incredible pain that I can't comprehend it."

The children have been shielded as much as possible from harsh truths, spared news of other attacks and the disadvantages and discrimination that lie ahead, Montanti said.

Baraka, for one, does not know his father is accused of involvement in his attack six months ago and is under arrest in Tanzania.

Many attacks on albino children involve parents or close relatives, Rwela said.

Emmanuel can recount his ordeal in hesitant English but has a severe speech impediment. His attackers chopped off one arm and the fingers of the other and tried to pull out his tongue and teeth.

He stutters as he describes the attack by strangers wielding machetes and a hammer as he played outside. He spent five months recovering in a local hospital.

Courtesy of the Philadelphia Shriners Hospital for Children, he has been fitted with a hook for one arm and a toe was grafted on his other arm to help form a grip.

Like many with albinism, Emmanuel has poor vision. He holds books and papers inches from his face as he reads and helps Baraka practice writing his name in block letters.

Montanti said she made sure their time in America was filled with good memories as the children, sensitive to light, donned sunglasses, hats and plenty of sunscreen to play in the sun.

Mwigulu piped up that his favorite pastime was swimming, and Baraka lost his first baby tooth.

Emmanuel, blushing as the others giggled, said he liked seeing the topless women in Times Square who pose for pictures and solicit tips.

"They've had a wonderful summer," Montanti said. "It's safe, with a lot of love, activities and a lot of laughing."

(Reporting by Ellen Wulfhorst, editing by Tim Pearce. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, corruption and climate change. Visit www.trust.org)