Hereditary diseases. History of genetic engineering

Hereditary diseases arise from a change in hereditary information and can pass to descendants. Gene diseases depend on a mutation of one gene: autosomal recessive – sickle-cell anaemia, phenylketonuria, albinism; autosomal dominant – traits such as syndactyly (fused fingers); X-linked – haemophilia, colour blindness. In chromosomal and genomic diseases the number or structure of chromosomes is disturbed: Down syndrome (trisomy 21, 47 chromosomes), Klinefelter syndrome (XXY, in males), Shereshevsky–Turner syndrome (XO, 45 chromosomes, in girls). A congenital disease is present from birth but need not be hereditary: it arises during development of the foetus from factors such as infection, alcohol, smoking, some drugs, or nutrient shortage (iodine, folic acid). Reproductive health is complete physical, mental and social well-being in matters of the reproductive system. It is harmed by marriage between close relatives, alcohol, narcotics, smoking and sexually transmitted infections (HIV/AIDS). In Uzbekistan there is medical-genetic counselling before marriage and a screening system for pregnant women and newborns, which helps detect diseases early and start treatment.