Eugenia is a complicated process, and every new life may be influenced by genetic factors, immune factors, microbial infection, environmental quality, occupational factors, nutrition and food, perinatal diseases, iatrogenic factors, bad habits and other factors. ?
20%-25% of birth defects are mainly caused by gene mutation and chromosome aberration, about 10%-20% comes from environmental teratogenic sources such as physical, chemical and biological factors, and 60%-65% of the reasons are unknown, which may mostly come from the joint action of genetic and environmental factors. Therefore, the work of prenatal and postnatal care should start with improving excellent genetic quality, preventing and eliminating environmental teratogenic factors, and be a systematic project from prenatal parental health care to postpartum health care and education. ?
Genetic factors?
The phenomenon of "parent-child similarity" between heredity and variation, including similarities in structure, function, appearance and disease, is called heredity. Some children are very much like their parents. "As you sow, you reap", which is almost completely expressed according to the parents' model, that is, inheritance. Although parents and children are similar, there are also differences, such as some traits and blood types. This phenomenon of "parent-child dissimilarity" is called variation. Genetic variation is an indispensable life phenomenon of living things. Heredity ensures the stability of all kinds of living things and makes them pass on from generation to generation. Variation makes organisms evolve, and it is also the result of variation that the predecessors changed from apes to modern people more than 0/000 years ago. ?
The human body is composed of about1000 trillion cells, which are divided into somatic cells and sex cells, and sex cells are the material basis of inheritance. Genetic information is realized through the "carriers" in parents' sperm and eggs-chromosomes and genes. Chromosome is composed of deoxyribonucleic acid (DNA), which is a double-stranded spiral long chain and highly twisted and folded. The reason is that there are about 2000 genes on each pair of chromosomes, and each gene has a fixed position. Genes determine genetic traits. ?
A fertilized egg is a bridge between a new generation and future generations. Chromosomes and genes are passed on to the next generation through sperm cells and replicate themselves. If chromosome and gene variation disturb normal weight activity, it is a pathological phenomenon. ?
Hereditary disease Hereditary disease refers to a disease in which the chromosome or gene of human genetic material changes abnormally, resulting in abnormal fetal structure and function. It is caused by the change of genetic material in the parental germ cells or fertilized eggs that develop into individuals, excluding diseases caused by gene mutation and chromosome aberration in somatic cells. Genetic diseases can occur in all tissues and organs of the human body. Genetic diseases have their own characteristics and laws. First, it is congenital, mostly lifelong, but congenital diseases are not all genetic diseases; Second, it is familial, which is passed on to the members of the same family in a vertical way and can be passed down from generation to generation; It can also be passed down from generation to generation, either explicitly or implicitly. Familial diseases are mostly hereditary diseases, but family does not directly mean heredity. ?
Monogenic genetic disease: Genetic disease caused by gene mutation. 4403 species have been found in 1986, among which there are more than 3000 species in China, and about 10% of the population is affected. Its inheritance modes are divided into autosomal dominant inheritance, recessive inheritance, X-linked dominant inheritance, recessive inheritance and Y-linked inheritance. ?
Polygenic genetic diseases: several pairs of genes work together and are often influenced by both genetic and environmental factors. Although there are only a few dozen kinds, each kind is common, and the number of people involved is about 20%. ?
Chromosome diseases: diseases caused by abnormal chromosome number or structure, which can be divided into autosomal diseases and sex chromosome diseases. 1986 667 kinds of chromosome diseases were found in medicine, involving 1%.