Uganda has opened its first clinics specifically set up to help thousands of children who have a mysterious fatal condition known as nodding syndrome.The centres in the north - where the disease is most common - are to control the worst of the symptoms.The disease's cause is unknown, but it affects only children - who suffer from seizures, stunted physical and mental growth and nodding of the head.There have also been cases of the disease in South Sudan and Tanzania. Managing symptomsMore than 200 sick children turned up on Monday for treatment in the centres in the districts of Kitgum, Pader and Ramor, Uganda's Commissioner for Health Services Dr Anthony Mbonye told the BBC.Health workers cannot offer definitive treatment - until doctors find out what lies at the root of the disease - but, Dr Mbonye says, they have been trained to help improve the lives of children by managing the neurological symptoms.Anti-epileptic drugs have been effective in treating nodding disease patients, according to the World Health Organisation.Nodding syndrome causes children to spasm uncontrollably - and eventually to waste away and die.The BBC's Ignatius Bahizi in Kampala says a local MP, Beatrice Anyor, has spearheaded a campaign to press the government to deal more effectively with the disease, which, he says, has caused huge anxieties in rural communities.Uganda's health ministry has recorded 3,000 cases and almost 200 deaths since 2010.