As science advances, in particular the rapid development of molecular genetics, people have found more than 3,000 kinds of genetic diseases, of which approximately 250 species in the pathogenesis of male-only, women have little or no illness. This is why?
We all know that human cells have 23 pairs of chromosomes, of which 1 (2) is decisive of sex chromosomes females are XX males and XY. Chromosomes carry decided on human genes of various characters of more than 50,000 more. If genes mutate, disease can occur, and can pass on to future generations. If the genes in chromosome, sex-linked inheritance occurs. Genes on the x chromosome, is called x-linked genetic diseases or X-even. As long as a single x chromosome carrying genes to pathogenesis of called x-linked dominant genetic disease, the disease rarely, pathogenesis of both men and women. Only two same location on the x chromosome are called x-linked recessive disease genes pathogenesis of genetic diseases, the illness more common. Because women it is difficult to encounter two chromosomes to the same location is a pathogenic situation, a can be another x chromosome genes are often masked by the normal gene on the x chromosome, so show no symptoms, but carriers and carriers of the gene. Men are different, there is only one x chromosome, if their genes, there is no corresponding normal genes to cover up, and onset. Usually if the mothers are carriers of the gene, father normal, patients with one-second may be in the son, daughter one-second may be in gene carriers. This is the reason why some genetic diseases only to men. Genetic diseases to men like this a lot, here are several common diseases:
Recommended reading >>> pregnant preparation-bypassing the minefield predictive genetic disease affecting genetic disease second child
Hemophilia died from hemorrhage more than boys for haemophiliacs, lacking an important blood coagulation in patients with factor-factor VII, such as trauma hemorrhage caused by a variety of reasons, blood cannot be solidified, and ultimately death due to excessive bleeding. At present, this protein has a large number of supply, thereby greatly reducing the mortality rate.
Duchenne muscular dystrophy in the pathogenesis of about 4 years old, generally not more than 7 years old. Thigh muscle atrophy, bold of leg weakness, walking posture like a duck, gradually paralyzed in a few years. Most of the patients died in about 20 years old. There is currently no effective treatment methods.
In patients with fragile x chromosome are low in patients with smart males. Appearance is characterized by outstanding forehead and Chin, nose and nasolabial fold too long; large \"prominent ears\" hand, foot and somewhat thick. Patients with giant cell is another important sign. 75% of patients in intelligence is low, low IQ is 50~70;25% is serious, IQ below 50.
Color blindness because this disease is not life-threatening, so the couple at the same time with the possibility of disease genes is more. So, the next generation of women from the parent each receive the possibilities of the x chromosome of a gene, thus showing symptoms. However, according to statistics, 14 times times the incidence in men is women. This disease can affect the youth on vocational and professional choices.
Recommended reading >>> and prenatal diagnosis of genetic disease diagnosis which can do family genetic disease to pregnant?
Patients with congenital absence of gamma globulin, hereditary deafness hereditary optic nerve atrophy, also are x-linked recessive hereditary disease.
In short, there is lack of specific treatment methods for such diseases. Can only be based on prevention, and resolutely intermarriage. Where this type of family history of genetic disease or birth of sick children, women, prenatal diagnosis of pregnancy must be done again, generally only female foeticide, prevent children born to the family and social burden. Currently, foreign is fetal diagnosis, which can retain is not suffering from genetic diseases of the male fetus. Have a family history of genetic disease of young people, should get genetic counseling help before getting married.
