Genetics of Mendelian Diseases in Qatar

Inclusion Criteria: * All included individuals must provide informed consent * All genetic disorders are included * All ethnic backgrounds are accepted * Disease must be genetic with no evident environmental cause * Evidence of Mendelian Transmission determined by fulfilling one of the following criteria: * Multiple affected family members (at least first degree relative with disease) * History of consanguinity * Severe disease in newborn in the absence of family history * Sydromic disease in single individuals * Congenital abnormality affecting major organ system(s) * Mendelianized extremes of common disease (eg sever familial diabetes/ obesity/ hypertension) Exclusion Criteria: * Individuals who do no consent to be included * Mendelian disease for which a gene mutation has already been identified * Individuals for which a molecular diagnosis has already been established by alternative method * Disease for which an environmental factor is most likely the cause * Disease for which late age of onset rule out Mendelian transmission * Common diseases for which late age of onset rule out Mendelian transmission