Punjabs finance minister Rana Asif Mahmood (also fired this year by the Supreme Court) is a Christian, as was his father, Rana Taj Mahmood. A few months ago, someone mistakenly recorded Asif Mahmoodsfaith in the national database as Islam. Mahmood now cannot change this because the punishment for leaving Islam is death. Once a Muslim, even by someones mistake, always a Muslim. This is not the saying of some cleric, it is the order of Pakistans chief justice Iftikhar Muhammad Chaudhry.
In Pakistan, no Sikh can become president [Article 41 (2)], no Christian can become prime minister (Article 91-5). The real villain is, of course, the Hindu. This is what Pakistani children are taught in class V: The Hindu has always been an enemy of Islam and Hindus worship in temples, which are very narrow and dark places, where they worship idols. In class VI: Hindus live in small, dark houses and Partition happened because the Congress demanded that the Muslims should either embrace Hinduism or leave the country (taken from A.H. Nayyar and Ahmed Salims work The Subtle Subversion).