There are more than 3,360 single-gene genetic diseases (1 disease is determined by 1 gene pair), such as familial multiple nodules, osteogenesis imperfecta, psoriasis, hypercholesterolemia, polycystic kidney disease, neurofibroma, retinoblastoma, peroneal muscular atrophy, chondrodysplasia, ptosis, systemic autoimmune disease, xeroderma pigmentosum, ichthyosis and so on.
Autosomal dominant genetic diseases (polydactyly, syndactyly, colonic polyps)
Autosomal recessive genetic diseases (phenylketonuria, congenital deafness, high myopia, etc.). ). About 10% patients with half of X chromosome recessive genetic disease (hemophilia) are involved.
Polygenic genetic diseases (each disease is caused by multiple pairs of genes and environmental factors), although the incidence is small, but the incidence is high, mostly common and frequently-occurring diseases. Such as essential hypertension, bronchial asthma, coronary heart disease, diabetes, rheumatoid arthritis, schizophrenia, epilepsy, congenital heart disease, peptic ulcer, varicose veins of lower limbs, glaucoma, kidney calculi's disease, spina bifida, anencephaly, cleft lip, cleft palate and deformed foot.
Its characteristics are: 1. Family reunion II. Greatly influenced by the environment. The number of people involved is about 20%.
There are nearly 500 kinds of chromosomal diseases (genetic diseases caused by chromosomal abnormalities), such as congenital stupidity (tongue coating dementia), primary microtorchiasis, congenital ovarian hypoplasia, hermaphroditism and so on. The number of people involved is about 1%.
One of the most effective methods is to advocate and practice eugenics: 1. Prohibition of consanguineous marriage: it can greatly reduce the probability of recessive genetic diseases.
2. Do prenatal diagnosis.
3. Couples with a history of genetic diseases should also have genetic counseling, mainly to investigate family history.
4. Giving birth at an appropriate reproductive age (24-29 years old)
[Edit this paragraph] Common genetic diseases
Hereditary diseases refer to diseases caused by changes in genetic material. It is congenital, lifelong and familial. There are many diseases and high incidence. At present, more than 3000 genetic diseases have been found, and it is estimated that about 3 ~ 10 newborns suffer from genetic diseases of different degrees.
1. Hypertension
Genetic risk: ★★★★★★★
Scientists have successfully bred a kind of "hereditary spontaneous hypertension" mice. This kind of mice will pass on the gene of hypertension from generation to generation, and their offspring will suffer from hypertension with 100%, which is the most typical example of the close relationship between hypertension and heredity.
At present, most scholars believe that hypertension is a polygenic genetic disease. Through the family survey of hypertensive patients, it is found that the probability of their children suffering from hypertension in the future is as high as 45%; If one parent suffers from hypertension, the probability of children suffering from hypertension is 28%; The probability that a child's blood pressure is normal is only 3%.
Prevention and control principle
1. Keep monitoring blood pressure, normally at least 1 time a year.
2. Limit salt and supplement potassium. Gradually control the daily salt intake to 5g, and eat more fruits and vegetables rich in potassium (such as bananas, walnuts, lotus seeds, parsley, amaranth and spinach). ).
3. Prevent overweight and obesity.
4. Quit smoking and limit alcohol.
2. Diabetes
Genetic risk: ★★★★★★★
Diabetes has obvious genetic susceptibility (especially the most common type 2 diabetes in clinic). Family studies have found that the prevalence of diabetes in people with positive family history is significantly higher than that in people with negative family history. Children whose parents have diabetes are 15 ~ 20 times more likely to have diabetes than ordinary people.
Prevention and control principle
The "external causes" of diabetes are excessive calorie intake, reduced activity, obesity, smoking and excessive psychological pressure. Conversely, avoiding the above factors can prevent diabetes. In terms of diet, it is necessary to achieve a reasonable mix of grain, meat, eggs, milk, vegetables and fruits, and pay attention to the balance between intake and consumption. Always measure your weight. If you gain weight, you will definitely consume too many calories. At this time, you should review your diet and increase exercise.
3. Dyslipidemia
Genetic risk: ★★★★
There are many reasons for abnormal blood lipid metabolism, and genetic factors are one of them. With the development of medicine, it is found that a considerable number of patients with dyslipidemia have one or more genetic defects. Dyslipidemia caused by genetic defects has family aggregation and obvious genetic tendency, which is commonly known as familial dyslipidemia in clinic.
Prevention and control principle
The most important thing is to emphasize "open your legs and close your mouth". On the one hand, the diet should be properly restricted, but the types of food should be as rich as possible. Choose low-fat foods (vegetable oil, yogurt), increase vitamins and cellulose (fruits, vegetables, bread, cereals), and control weight. At the same time, strengthen exercise, let the heat be consumed, so as to avoid fat accumulation in the body.
4. Breast cancer
Genetic risk: ★★★★
Breast cancer has obvious familial genetic tendency. Epidemiological investigation shows that 5% ~ 10% of breast cancer is familial. If a close relative has breast cancer, the risk will increase by 1.5 ~ 3 times; If two close relatives have breast cancer, the prevalence rate will increase seven times. The younger the onset age, the greater the risk of breast cancer in relatives.
Prevention and control principle
People with a family history of breast cancer should pay special attention to self-examination to find clues to breast cancer and treat it as soon as possible. Breast lump is the most common sign of breast cancer, which is different from proliferative breast lump. It is often single, irregular in shape, hard in texture, poor in mobility, mostly painless, and has no obvious relationship with menstrual cycle. In addition, if you find nipple eczema, pus and shrinkage, you should also pay attention to it and go to the hospital for further examination.
5. Gastric cancer
Genetic risk: ★★★★
Patients with gastric cancer have obvious family aggregation. The survey found that the risk of first-degree relatives (parents, brothers and sisters) of patients with gastric cancer is three times higher than that of the general population on average. The famous Napoleon family, such as his grandfather, father and three sisters, all died of gastric cancer. Seven people in the family, including himself, all suffered from gastric cancer.
Prevention and control principle
Risk factors of gastric cancer include lack of physical exercise, depression, smoking, preference for smoked food, preference for heavy salt diet, excessive meat intake, Helicobacter pylori infection and gastric ulcer. Favorite fungi and fresh fruits are the protective factors of gastric cancer. It is worth noting that the phenomenon of family aggregation of gastric cancer may be related to the co-infection of Helicobacter pylori. Those with a family history of gastric cancer should go to the hospital to monitor whether there is such bacterial infection, and if there is, they should be treated in time.
6. Colorectal cancer
Genetic risk: ★★★★
Colorectal cancer caused by familial inheritance accounts for 10% ~ 15% of the total number of patients with colorectal cancer. People with colorectal cancer in their relatives are 3-4 times more likely to suffer from this disease than ordinary people. If two or more close relatives (parents or brothers and sisters) in the family have colorectal cancer, it is a high-risk group of colorectal cancer.
Prevention and control principle
People with a family history of colorectal cancer should eat more fresh food, eat less salty and smoked food, eat less moldy food, drink less and quit smoking. If the following symptoms appear, you should go to the hospital for examination in time:
① The defecation habit changes, the frequency of defecation increases, or diarrhea and constipation appear alternately. ② Stool with purulent blood or mucus stool. ③ The stool becomes thin and deformed, and defecation is laborious. ④ There is a feeling of defecation, but no defecation.
7. Lung cancer
Genetic risk: ★★★
Foreign research institutions have conducted a follow-up survey of more than 102000 Japanese middle-aged and elderly people for 13 years. Among them, 79 1 case had lung cancer. The researchers compared lung cancer patients with non-lung cancer patients and found that the former was twice as likely to get sick as the latter. The heredity of lung cancer is particularly obvious in women.
Prevention and control principle
The occurrence of lung cancer is closely related to smoking, especially those with a family history of lung cancer, so they must stay away from tobacco and passive smoking. If you have symptoms such as irritating cough and blood in sputum, especially the above-mentioned high-risk groups, you should seek medical advice as soon as possible. If early detection and standardized treatment can be achieved, the cure rate of lung cancer can reach 70%.
8.asthma
Genetic risk: ★★★★★★★
At present, most scholars believe that the genetic factors of asthma are greater than the environmental factors. If both parents suffer from asthma, the probability of their children suffering from asthma can be as high as 60%; If one parent suffers from asthma, the probability of the child suffering from asthma is 20%; If neither parent has asthma, the probability of children suffering from asthma is only about 6%. In addition, if family members and their relatives suffer from allergic diseases such as allergic rhinitis, skin allergy or food and drug allergy, it will also increase the possibility of asthma in future generations.
Prevention and control principle
Adult asthma mostly occurs in childhood, and early treatment in childhood is the key to reduce the incidence in adulthood. People with a family history of asthma should avoid all kinds of environmental factors that cause asthma, such as inhaling various allergic substances (allergens), respiratory virus and bacterial infections, smoking and air pollution, which play a role in triggering and fueling the onset and aggravation of asthma. Usually, we should do a good job in cleaning the living room, living and working environment, quit smoking, and actively prevent and treat respiratory infections in time.
9. Depression
Genetic risk: ★★★★★★★
Many studies have found that the occurrence of depression is closely related to genetic factors. The probability of depression in relatives of depressed patients is much higher than that of ordinary people, which is about 10 ~ 30 times, and the closer the blood relationship, the higher the probability of depression. According to foreign reports, the probability of depression among relatives of patients with depression is: the first-degree relatives (parents, compatriots and children) are 14%, the second-degree relatives (uncles, aunts, uncles, grandparents or grandsons and nephews) are 4.8%, and the third-degree relatives (cousins) are 3.6%.
Prevention and control principle
Prevention and treatment of depression should focus on early detection, early diagnosis and early treatment. If you often feel depressed, lose weight obviously, suffer from insomnia or sleep too much, fidget, lose concentration, have suicidal thoughts, etc. You should go to the hospital for examination and treatment in time.
10. Senile dementia
Genetic risk: ★★★★
After long-term research, scientists found that Alzheimer's disease is a polygenic genetic disease. The study found that patients with Alzheimer's disease in their parents or brothers were four times more likely to develop Alzheimer's disease than patients without family history.
Prevention and control principle
If you have a family history of Alzheimer's disease, you should have an examination after 50 to see if you have mental retardation, so as to take some measures to treat it in time.
In addition to genetic factors, people with low education are prone to Alzheimer's disease, while those with formal education delay the onset age by 7 ~ 10 years compared with those without education. In addition, long-term depression, solitude, low education and language level, widowhood and non-remarriage, non-participation in social activities, and lack of physical and mental activities are also easy to cause Alzheimer's disease.
The incidence of the above genetic diseases adds up to about 30%, and there is a trend of increasing year by year. Therefore, it can no longer be generalized that genetic disease is only a rare disease. Preventing the birth of children with genetic diseases is an important eugenic means to improve the quality of our population.
Most genetic diseases cannot be cured.
Because modern medicine can't change the genes of people who have been born, as long as the pathogenic genes are still there, they can't be cured. But some diseases can be alleviated by continuous medication.
[Edit this paragraph] Family hereditary diseases
Hereditary diseases are diseases caused by changes in genetic material.
Hereditary diseases are congenital, familial, lifelong and hereditary.
The types of genetic diseases can be roughly divided into three categories:
First, monogenic diseases.
A single gene often shows functional changes, can't produce protein, has metabolic dysfunction, and forms metabolic genetic diseases. Monogenic diseases are divided into three types:
1. Dominant inheritance: If one parent has a dominant gene, once it is passed on to the next generation, it will get sick, that is, there will be sick offspring, and it will be passed down from generation to generation, such as polydactyly, syndactyly, primary glaucoma, etc.
2. Recessive inheritance: such as congenital deafness, high myopia, albinism, etc. It is called recessive genetic disease because the parents of children are often normal in appearance, but they are all carriers of pathogenic genes.
3. Sex-linked inheritance, also known as sex-linked inheritance, is related to gender, such as hemophilia, whose mother is the carrier of the disease-causing gene. Another example is red-green color blindness, which is cross-inheritance. The son comes from the mother and is the carrier of the pathogenic gene, and the daughter comes from the father, but the incidence rate of men is much higher than that of women.
Second, polygene inheritance: it is caused by the influence of various gene changes, and it is the relationship between genes and traits. People's body length, body shape, intelligence, skin color, blood pressure and other traits are polygenic inheritance, as are cleft lip and palate. In addition, polygenic inheritance is greatly influenced by environmental factors, such as asthma and schizophrenia.
3. Chromosome abnormality: due to abnormal chromosome number or arrangement position; The most common type is congenital stupidity. Such children have dull face, mental retardation, wide eye distance, strabismus, tongue coating dementia, hand penetration, and often complicated with congenital heart disease.
If you don't carry the disease-causing gene, the above genetic diseases will definitely occur.
In fact, almost all diseases are related to genes and environment! Heredity can be divided into qualitative traits and quantitative traits according to biological characteristics! The so-called quality traits are the differences between white people and yellow people, which are mainly determined by heredity and less affected by environmental factors. That is the difference between men and women! The quantitative characters are the weight of rice, the height of people, the color depth and so on. These are called quantitative traits. Quantitative traits are determined by multiple genes, and the number of genes is generally difficult to measure, because the error can differ by an order of magnitude. So we mainly talk about the total effect of genes! Quantitative characters are greatly influenced by the environment. It can be said that it exceeds genetic factors!
In a word, most diseases are the result of the interaction of environmental factors and genetic factors.
[Edit this paragraph] Diet therapy
Some genetic diseases can be prevented by controlling diet, so as to obtain therapeutic effects. For example, the pathogenesis of phenylketonuria is the lack of phenylalanine hydroxylase, which leads to the accumulation of phenylalanine and phenylpyruvic acid in the body and may lead to mental retardation or idiots in children. However, if the diagnosis is accurate, it is best to start early prevention and treatment at 7- 10 days after birth, and give the baby a low phenylalanine diet within 3 months after birth, such as rice, Chinese cabbage, spinach, potatoes, mutton, etc., which can promote the normal growth and development of the baby. When the children grow up and go to school, then relax the dietary restrictions appropriately.
For another example, 5% people in the provinces south of the Yangtze River in China suffer from hereditary glucose-6- phosphate dehydrogenase deficiency, which manifests as hemolytic anemia in Linqing, which can be life-threatening in severe cases. This kind of patients are particularly sensitive to broad beans. Eating broad beans can cause acute hemolytic anemia, so it is also called "silkworm disease". Broad beans and their products should be strictly fasted for such patients. At the same time, the disease can also cause drug-induced hemolysis, infectious hemolysis and hereditary non-spherical cell hemolytic anemia, so we must be cautious when using drugs at ordinary times.
[Edit this paragraph] Drug therapy
Drugs often play an auxiliary role in the treatment of genetic diseases, thus improving the patient's condition and alleviating the pain. Mainly symptomatic treatment, such as taking painkillers to alleviate the pain of patients. It can also improve the metabolism of the body, such as hepatolenticular degeneration, mainly due to the disorder of copper metabolism in the body, which increases the level of copper in the blood and leads to fetal malformation. You can take drugs to promote copper excretion and limit the consumption of copper-containing foods to maintain the normal level of copper in the body and achieve good therapeutic effects. Some diseases, such as congenital immunoglobulin deficiency, can be treated with immunoglobulin preparations.
[Edit this paragraph] Surgical treatment
Surgical correction refers to the method of surgical removal of some organs or surgical repair of some organs with morphological defects. For example, spherocytosis, due to genetic defects, the osmotic fragility of patients' red blood cells is obviously increased, and red blood cells are spherical, which are easily destroyed when passing through the spleen and spleen sinus, causing hemolytic anemia. Splenectomy can be performed. Splenectomy can not change the abnormal morphology of red blood cells, but it can prolong the life of red blood cells and obtain therapeutic effect. Deformities of fingers, rabbit lips and external genitalia can be corrected by surgery. For another example, body odor is also a genetic disease, but as long as the glands under the armpits of patients are gouged out, patients can be eliminated.
Gene therapy
Gene therapy is a basic and promising method. Human genetic material can also be borrowed from other creatures, just like the story of "shrimp borrows eyes from earthworms". That is, normal genes are injected into cells with gene defects to achieve therapeutic purposes. Gene therapy is simple to say, but it is actually a rather complicated problem. First of all, we should find out the defective genes from hundreds of thousands of genes, and at the same time, we should prepare the corresponding normal genes, and then transfer the normal genes into cells to replace the defective genes and express them normally. This treatment method is still in the stage of research and exploration.
Especially at the present stage when gene therapy has not been thoroughly studied, the above-mentioned simple methods can only treat a few hereditary diseases, and this kind of treatment only has the effect of palliative, that is, the so-called "phenotype therapy", which can only eliminate the pain of a generation and never touch the disease-causing gene itself. Those pathogenic genes will continue to be passed on to the offspring of patients according to the inherent laws.
[Edit this paragraph] Analysis and research
Diseases caused by changes in genetic material before or during the formation of fertilized eggs. Some people think that only diseases determined by parents' genetic factors are genetic diseases, and this understanding is not comprehensive enough. For example, some chromosome aberrations are not determined by parents' genetic factors, but are produced during the formation of fertilized eggs. Chromosome aberration is traditionally included in the category of genetic diseases. Others think that all diseases affected by genetic factors are genetic diseases, which is not accurate, because in all human diseases, except for a few (such as fractures caused by trauma) which are completely caused by environmental factors and are not affected by genetic factors, almost all diseases are the result of the interaction of environmental and genetic factors, but their influence on the occurrence of diseases is different. Even for diseases with obvious environmental factors such as bacterial infection and post-traumatic epilepsy, there are differences in susceptibility among different individuals, and this difference is also affected by genetic factors. It is impossible to classify all these diseases as genetic diseases. Diseases that are completely determined by genetic factors (Class A, such as 2 1 trisomy syndrome) and diseases that are completely determined by environmental factors (Class D, such as traumatic fractures) are rare, while most human diseases are basically determined by genetic factors in Class B and Class C, but they need certain incentives in the environment to get sick. For example, children with phenylketonuria will get sick after taking phenylalanine after birth. Class C refers to diseases in which both genetic factors and environmental factors play a role, such as hypertension and infection. But the heritability of different diseases is different, that is, the greater the influence of genetic factors, the higher the heritability. So theoretically, A, B and C are all hereditary diseases, but C, such as infection and post-traumatic epilepsy, does not belong to the category of hereditary diseases. Hereditary diseases are different from congenital diseases, the latter refers to diseases that have been manifested at birth. Although many genetic diseases have been shown at birth, some genetic diseases are normal at birth, but they begin to show up gradually after a few days, months, even years and decades, which obviously does not belong to congenital diseases. On the other hand, congenital diseases are not all caused by genetic factors. For example, a congenital malformation caused by radiation during pregnancy is not a genetic disease. Hereditary diseases are also different from familial diseases. Although some family members of the same family have the same genetic basis, the transmission laws of different genetic diseases between parents and offspring are complex and diverse. Some genetic diseases (such as recessive genetic diseases such as albinism) may not have a family history. On the other hand, familial diseases may also be caused by non-genetic factors (such as the same living conditions). For example, the lack of vitamin A in the diet makes many family members suffer from night blindness.
In the past, genetic diseases were considered as rare diseases, but with the development of medicine and the improvement of people's living standards, some infectious diseases and nutritional diseases that seriously threatened human health in the past have been controlled, and genetic diseases have become a more prominent problem. For example, 19 14, a survey on the cause of death of children in Britain, showed that non-hereditary diseases (such as infection, tumor, etc. ) accounted for 83.5%, while hereditary diseases only accounted for 16.5%, but by the late 1970s, both diseases accounted for 50%. So is China. Infectious diseases play an important role in the causes of death of children in Beijing in 195 1 year. However, in the analysis of the causes of death of children in 1974 ~ 1976, congenital malformations accounted for 23.4% of all deaths, ranking first, and among these malformations, 3 ~ 65438 cases were hereditary diseases. On the other hand, there are many genetic diseases. With the development of biology and medicine, new genetic diseases have been discovered in recent years. The table 1 shows that there are about 4000 known genetic diseases from 1958 to 1982.
A Brief History Maupertuis, a Frenchman in the18th century, was the first to make a family survey of genetic diseases, and he analyzed the genetic mode of albinism. 18 14 ADAMS published a paper on the heritability of clinical diseases, which is considered to be the earliest article on hereditary diseases in modern times. 1908 A.E. Garaude put forward the concept of "congenital metabolic abnormality" for the first time, which linked heredity and metabolism, and thought that the genetic law of congenital metabolic abnormality such as uracil could be explained by Mendel's law, making an epoch-making contribution to medical genetics.