Nov 28 (Reuters) - A new killing in Burundi and a wave of killings in Tanzania have terrified albinos who are being targeted apparently for their body parts, which are sold to witchdoctors. Here are some facts: * THE EFFECTS: -- People with albinism are at risk of isolation because the condition is often misunderstood. Social stigmatisation can occur, especially within communities where the race or paternity of a person with albinism may be questioned. * ATTACKS IN AFRICA: -- More than 30 albinos have been killed in Tanzania this year. The latest three incidents occurred days after a march in Dar es Salaam to condemn the killings. There are more than 200,000 albinos in Tanzania. -- Burundi said a young boy has been killed, the fourth albino to be murdered this year. Authorities there say it was at the prompting of Tanzanian traffickers seeking their body parts for witchcraft. Twenty five albinos have fled village homes near Burundi's border with Tanzania, to the small town of Ruyigi in fear for their lives. They are under police protection around the clock. * WHAT IS ALBINISM? -- The word "albinism" refers to a group of inherited conditions. People with albinism have little or no pigment in their eyes, skin, or hair. They have inherited altered genes that do not make the usual amounts of a pigment called melanin. -- Albinism affects people from all races. Most children with albinism are born to parents who have normal hair and eye colour for their ethnic backgrounds. -- While most people with albinism have very light skin and hair, not all do. Oculocutaneous albinism (OCA) involves the eyes, hair and skin. Ocular albinism (OA), which is much less common, involves primarily the eyes, while the skin and hair may appear similar to or slightly lighter than that of other family members. -- Eye problems in albinism result from abnormal development of the eye because of lack of pigment. Albinos may have varying degrees of partial sightedness; either near-sighted or far-sighted. Individuals with these conditions may be helped by the use of glasses, but their vision cannot be corrected completely. Another common condition is nystagmus, an involuntary movement of the eyes back and forth. * WHAT'S THE TREATMENT? -- There is no cure for the disorders covered by albinism, but treatments can help the symptoms. -- Avoiding exposure to UV light and using high-factor sunscreen are essential. -- Ante-natal testing for the condition is possible. Sources: Reuters/NOAH, National Organisation for Albinism & Hypopigmentation/BBC/Alibinism.med: