The natural history and the national pre-marital screening program in Saudi Arabia.

The genetic disorders are chronic in nature and, therefore, require continuous support and health care. Consequently, the genetic diseases cause formidable economic and psychosocial burdens on the family with negative reflection on the community at large. The genetic diseases are a heterogeneous group that result in varieties of chronic health ailment as a result of defects in the genetic material. The congenital malformations and some genetic defects may result from exposure to radiation, pharmaceutical drugs, the exposure of the mother during pregnancy to certain infectious diseases, such as rubella, toxoplasma or viruses. It may also result as a side effect of chronic diseases, including diabetes, hypertension or varieties of environmental factors, or both. The other group of genetic diseases are transmitted from parents to the offspring through a specific pattern of inheritance exemplified by recessive genetic disorders. This group includes the sickle cell gene, the thalassemias, the hemophilias, inborn errors of metabolism and red cell enzymopathies. The main etiological factors of genetic diseases and congenital malformations are 1) Genetic defects which are transmitted to offspring through carriers of affected parents. 2) Mutations in the genetic materials due to spontaneous mutations, exposure of the mother during pregnancy to infectious diseases, such as rubella and toxoplasma, receiving certain teratogenic drugs during pregnancy, exposure of the mother to ionizing radiation during pregnancy such as x-ray and chronic diseases of the mother, such as diabetes mellitus. 3) Others such as difficult labor or injury to the baby, during or after labor. This paper reviews the natural history of common blood genetic disorders and the means of prevention and control, focusing on pre-marital screening as a means of prevention.