Hereditary diseases of man. List. The most common and dangerous diseases
At the beginning of the 21 century there are already more than 6 thousand types of hereditary diseases. Now in many institutes of the world, hereditary human diseases are studied, the list of which is huge.
The male population has an increasing number of geneticdefects and are less likely to conceive a healthy child. While all the causes of the development of vices are unclear, one can assume that in the nearest 100-200 years science will cope with the solution of these problems.
What are genetic diseases? Classification
Genetics as a science began its own path of investigationsince 1900. Genetic diseases are those that are associated with deviations in the gene structure of a person. Deviations can occur in either one gene or several.
- Autosomal dominant.
- Autosomal recessive.
- Clutched with the floor.
- Chromosomal diseases.
The probability of a child's illness in autosomal dominant deviation is 50%. At autosomal recessive - 25%. Diseases linked to the sex are those that carry a damaged X chromosome.
Here are some examples of diseases, according to the above sound classification. So, to dominant-recessive diseases are:
- Marfan's syndrome.
- Paroxysmal myoplegia.
- Albright's disease.
- Muscular dystrophy.
- Pharby's disease.
Also on hearing are chromosome hereditary human diseases. The list of chromosomal abnormalities is as follows:
- Syndrome Shereshevsky-Turner.
- Klinefelter's syndrome.
- The cat's screaming syndrome.
- Down Syndrome.
The polygenic diseases include:
- Dislocation of the hip (congenital).
- Heart defects.
- Splitting of the lips and the sky.
The most common gene anomaly -Syndactyly. That is, the fusion of the fingers. Syndactyly is the most innocuous disorder and is treated with surgery. However, this deviation is accompanied by other more serious syndromes.
What diseases are most dangerous
Of those listed diseases can be identifiedthe most dangerous hereditary human diseases. Their list consists of those types of anomalies, where trisomy or polysomy occurs in the chromosome set, that is, when the presence of 3, 4, 5 or more is present instead of a pair of chromosomes. There is also 1 chromosome instead of 2. All these deviations occur due to a violation of cell division.
The most dangerous hereditary human diseases:
- Edwards Syndrome.
- Spinal muscular amyotrophy.
- Syndrome Patau.
- Canavan's disease.
- Other diseases.
Due to such violations, the child lives a year or two. In some cases, the deviations are not so serious, and the child can live up to 7, 8 or even up to 14 years.
Down Syndrome is inherited if oneor both parents are carriers of defective chromosomes. More precisely, the syndrome is associated with trisomy of 21 chromosomes (ie, 21 chromosomes 3, not 2). Children with Down's syndrome have strabismus, a crease on the neck, an abnormal shape of the ears, heart problems and mental retardation. But for the life of newborns, the chromosome abnormality does not carry.
Now statistics say that of 700-800children 1 is born with this syndrome. Women who want to have a child after 35 are more likely to give birth to such a baby. The probability is somewhere 1 to 375. But a woman who decided to have a baby in 45, has a probability of 1 to 30.
Type of inheritance anomaly - autosomal dominant.The cause of the syndrome is a disorder in the 10 chromosome. In science, this disease is called acrokraniodisphalange, if it is easier, then the syndrome is Apert. Characterized by such features of the structure of the body, as:
- Brachycephaly (violation of the ratio of width and length of the skull);
- fusion of the coronary sutures of the skull, as a result of which hypertension is observed (high blood pressure inside the skull);
- convex forehead;
- often mental retardation on the background of the fact that the skull squeezes the brain and does not allow growing nerve cells.
In our time, children with Apert syndrome are prescribed a surgery to increase the skull in order to restore blood pressure. And mental underdevelopment is treated with stimulants.
If the family has a child who has a syndrome diagnosed, the likelihood that the 2 children will be born with the same deviation is very high.
Syndrome of a happy doll and Canavan-van-Bogart-Bertrand disease
Let us also consider these diseases in more detail.Identify Engelman's syndrome can be anywhere from 3-7 years. Children have cramps, poor digestion, problems with coordination of movements. Most of them have strabismus and problems with facial muscles, which is why a smile is often on the face. The movements of the child are very constrained. For doctors, this is understandable when trying to walk a child. Parents in most cases do not know what is happening and especially with what it is connected. A little later, it is noticeable that they can not talk, they just try to mutter something inarticulate.
The reason that a child has a syndrome is a problem in the 15 chromosome. The disease is extremely rare - 1 case for 15 thousand births.
Another disease is Canavan's disease -characterized by the fact that the child has a weak muscle tone, he has problems with swallowing food. The disease is caused by the defeat of the central nervous system. The reason is the defeat of one gene in 17 chromosomes. As a result, nerve cells in the brain are destroyed with progressive rapidity.
Symptoms of the disease can be seen at 3 months old. Manifestation of Canavan is as follows:
- Muscular hypotension.
- Seizures appear at the age of one month.
- The child is not able to hold the head upright.
- After 3 months, tendon reflexes increase.
- Many children go blind by 2 years.
As we can see, hereditary human diseases are very diverse. The list given just for example is far from complete.
I would like to note that if both parentsthere is a violation in the same gene, then the chances of having a sick child are great, but if the anomalies in different genes, then you can not be afraid. It is known that in 60% of cases the chromosomal abnormalities in the fetus lead to miscarriage. But still 40% of these children are born and are struggling for their lives.