'
Научный журнал «Вестник науки»

Режим работы с 09:00 по 23:00

zhurnal@vestnik-nauki.com

Информационное письмо

  1. Главная
  2. Архив
  3. Вестник науки №5 (62) том 3
  4. Научная статья № 135

Просмотры  25 просмотров

Izmailova L.S., Miroshnichenko A.V., Sitdikova A.I., Khammatova E.N.

  


DOWN SYNDROME. SICKLE CELL ANEMIA *

  


Аннотация:
Down syndrome is a genetic disease caused by an anomaly of the 21st chromosome, which manifests itself in the form of mental retardation, heart defects and developmental disorders. It is often accompanied by a violation of the thyroid gland, hearing impairment, vision. There are 23 pairs of chromosomes in the human chromosome set. Sickle cell anemia is a hereditary hemoglobinopathy caused by the synthesis of abnormal hemoglobin S, a change in the shape and properties of red blood cells   

Ключевые слова:
Down syndrome, sickle cell anemia, genomic mutation, chromosomes   


УДК 61

Izmailova L.S.

Bashkir State Medical University

(Ufa, Russia)

 

Miroshnichenko A.V.

Bashkir State Medical University

(Ufa, Russia)

 

Sitdikova A.I.

Bashkir State Medical University

(Ufa, Russia)

 

Scientific advisor:

Khammatova E.N.

Teacher of the Department of Foreign Languages

with the course of the Latin language

Bashkir State Medical University

(Ufa, Russia)

 

DOWN SYNDROME. SICKLE CELL ANEMIA

 

AbstractDown syndrome is a genetic disease caused by an anomaly of the 21st chromosome, which manifests itself in the form of mental retardation, heart defects and developmental disorders. It is often accompanied by a violation of the thyroid gland, hearing impairment, vision. There are 23 pairs of chromosomes in the human chromosome set.

Sickle cell anemia is a hereditary hemoglobinopathy caused by the synthesis of abnormal hemoglobin S, a change in the shape and properties of red blood cells.

 

KeywordsDown syndrome, sickle cell anemia, genomic mutation, chromosomes.

 

INTRODUCTIUON

Genetics as a science originated in the 19th century, its discoverer was Grigory Mendel. He revealed to the whole world the discreteness (separation) of hereditary factors. He proved that in the structure of every living organism there are so-called genes (in his time they were not called that, he only showed that such exist) capable of transmitting hereditary factors. It is important to understand here that genes transmit not the trait itself – eye color or height, but the very possibility of the development of these signs. When Mendel made his discovery, no one was interested in his success. But already in 1900, three biologists rediscovered his law, making sure of the reliability of the latter.
Soon after the confirmation of the Mendelian Law, it was actively used – in just three years, new varieties of corn, beans, peas were bred; mammals were not left behind, the first experiments were conducted on rabbits and mice. At one time, Mendel made the most important discovery in natural science for the entire century, he just didn't find out about it. His laws helped genetics to quickly get ahead.
The second step in genetics can rightfully be considered the work of E. Wilson, T. Boveri and W. Satton. Continuing the theme of their predecessor, they found out that the genes they found are in chromosomes. They also proved that there are two types of emergence of new organisms: Mitosis – occurs by dividing the mother cell, followed by the appearance of a new one; Meiosis – occurs by the maturation of cells sexually.
Their work was continued by T. G. Morgan, who proved that the chromosomes in the cell nucleus are in linear order, and they can change their order during meiosis, which he called variability.
In recent years, with the use of modern technologies, genetic engineering has begun to develop, which allows a person to construct DNA chains. Simply put, you can take the strong genes of one organism and inoculate them with a weaker one, getting an almost perfect organism. Thanks to these opportunities, unimaginable prospects open up to people, because after conducting experiments on creatures such as rats and mice, modification of human genes will become available, allowing him to do unimaginable things.

 

Sickle cell anemia

Sickle cell anemia (S-hemoglobinopathy) is a type of hereditary hemolytic anemia characterized by a disorder of the hemoglobin structure and the presence of sickle-shaped red blood cells. The resulting hemoglobin S acquires the consistency of a highly polymeric gel and becomes 100 times less soluble than normal hemoglobin A after the loss of attached oxygen. As a result, erythrocytes carrying deoxyhemoglobin S become deformed and acquire the characteristic semi-lunar (sickle) shape. Altered red blood cells become rigid, poorly plastic, can clog capillaries, causing tissue ischemia, easily subjected to autohemolysis.

Sickle cell anemia is based on a gene mutation that causes the synthesis of abnormal hemoglobin S (HbS). The defect in hemoglobin structure is characterized by the replacement of glutamic acid by a valine in the ß-polypeptide chain.

Depending on the genotype, hematology distinguishes between heterozygous (HbAS) and homozygous (HbSS, drepanocytosis) forms of sickle cell anemia. Rare variants of the disease include intermediate forms of sickle cell anemia. They usually develop in double heterozygotes carrying one gene for sickle cell anemia and another defective gene, hemoglobin C (HbSC), sickle β-plus (HbS/β+) or β-0 (HbS/β0) thalassemia.

Symptoms of sickle cell anemia

Homozygous sickle cell anemia usually appears in children by the 4th or 5th month of life, when the HbS count increases and the percentage of sickle cells reaches 90%. In such cases, the early onset of hemolytic anemia in the child causes a delay in physical and intellectual development. Skeletal abnormalities are characteristic: tower skull, thickening of the frontal sutures of the skull in the form of a ridge, kyphosis of the thoracic spine or lordosis of the lumbar spine.

There are three periods in the development of sickle cell anemia: I - from 6 months to 2-3 years, II - from 3 to 10 years, III - over 10 years. Early signals of sickle cell anemia are arthralgia, symmetrical swelling of the limb joints, pain in the chest, abdomen and back, jaundice of the skin, splenomegaly. Children with sickle cell anemia are classified as frequently ill. The severity of the course of sickle cell anemia closely correlates with the concentration of HbS in red blood cells: the higher it is, the more severe the symptoms are.

 

Treatment

It is impossible to give the individual patient with sickle cell anemia an accurate prognosis of the severity of the disease. Although the molecular basis of the disease became known earlier than other monogenic diseases, treatment remains symptomatic only. No specific therapy preventing the formation of sickle-shaped red blood cells has been found. HbE persistence significantly reduces the severity of the disease Several pharmacological drugs aimed at increasing the HbF concentration are being investigated, with hydroxyurea approved for this purpose. Although gene therapy has a chance to improve or cure this disease, effective b-globin gene transplantation has not been achieved. Bone marrow transplantation remains the only treatment currently available that can help with sickle cell anemia.

Risks of inheriting sickle cell anemia

 Because sickle cell anemia is an autosomal recessive disease, future siblings of a sick child have a 25% risk of sickle cell anemia and a 50% risk of being sickle cell carriers. Using fetal DNA obtained by BVH or amniocentesis, a prenatal diagnosis can be made by detecting the mutation.

Example of sickle cell anemia. For the second time in six months, a married couple of Caribbean descent went to the emergency room with their 24-month-old daughter because the girl could not stand. There was no history of fever, infection, or trauma, and the medical history was otherwise unremarkable; previous exams were normal except for low hemoglobin and a slightly enlarged spleen. No pathology was found on the current examination, except for a palpable edge of the spleen and swelling of the feet.

The feet were painful on palpation, and the girl did not want to stand on her feet. Both parents had sibs who died in childhood from infections and other sibs likely to have sickle cell anemia. Given the history and repeated painful enlargement of the feet, the physician tested the child for the presence of sickle cell anemia by hemoglobin electrophoresis. The result of this test confirmed the presence of HbS.

 

Down Syndrome

People who have Down syndrome have learning difficulties, mental disability, a characteristic facial appearance, and poor muscle tone (hypotonia) in infancy.

Individuals with Down syndrome also have an increased risk for having heart defects, digestive problems such as gastroesophageal reflux or celiac disease, and hearing loss. Some people who have Down syndrome have low activity of the thyroid gland (hypothyroidism) - an organ in the lower neck that produces hormones.

Down syndrome can be diagnosed in infancy based on the characteristic clinical findings. When Down syndrome is suspected in a person, a genetic test called a chromosome analysis is performed on a blood or skin sample to look for an extra chromosome 21 (trisomy 21). Trisomy 21 means that each cell in the body has three copies of chromosome 21 instead of the usual two copies.

Having an extra number 21 chromosome interrupts the normal course of development, causing the characteristic clinical features of Down syndrome. Some people who have Down syndrome have an extra number 21 chromosome in only some of their body's cells. This type of Down syndrome is called mosaic Down syndrome.

A small number of individuals have Down syndrome because part of chromosome 21 becomes attached (translocated) to another chromosome before or at the time of conception. These individuals have two copies of chromosome 21, and additional material from chromosome 21 that is attached to another chromosome. The chromosomes of parents of a child with Down Syndrome caused by a translocation are studied to see whether the translocation was inherited.

Treatment for Down syndrome is based on the person's physical problems and intellectual challenges. Many babies who have Down syndrome do not have good muscle tone, which makes it harder for them to roll over and walk. Physical therapy can help with these problems.

About 40 - 60 percent of babies born with Down syndrome have a heart defect. Therefore, all newborns with Down syndrome have their heart checked with an electrocardiogram and an echocardiogram. When there is a heart defect present in an infant with Down syndrome, the infant is referred to a pediatric cardiologist for medical management or to a pediatric cardiac surgeon for early surgical repair. Some infants with Down syndrome have difficulties with swallowing or they may have blockages in their bowels. Surgery can be performed to correct these problems. Once corrected, they usually cause no further health issues.

Children with Down syndrome may have frequent colds and sinus and ear infections. These are treated early and aggressively to prevent hearing loss and chronic infections.

Low thyroid levels are more common in infants who have Down syndrome. It is recommended that thyroid level testing be performed at least yearly.

Some infants with Down syndrome have eye problems such as cataracts (cloudy lenses) or crossed eyes (strabismus). Surgery can help with these problems.

Sucking problems related to low muscle tone or heart problems may make breast feeding difficult initially. Occupational therapists, speech therapists, breast feeding consultants and support groups usually have specific resources for the mothers of infants with Down syndrome.

Intelligence in individuals with Down syndrome ranges from low normal to very slow to learn. At birth it is not possible to tell the level of intelligence a baby with Down syndrome will have. All areas of development including motor skills, language, intellectual abilities, and social and adaptive skills are followed closely in children with Down syndrome. Early referral, beginning at birth, to an early intervention program will help enhance development. Preschool programs for children with Down syndrome include physical, occupational, speech and educational therapies.

Many adults with Down syndrome have jobs and live independently.

Most cases of Down syndrome are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 21. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 21 in each of the body's cells.

Mosaic Down syndrome is also not inherited. It occurs as a random error during cell division early in fetal development. As a result, some of the body's cells have the usual two copies of chromosome 21, and other cells have three copies of the chromosome. Translocation Down syndrome can be inherited. An unaffected person can carry a rearrangement of genetic material between chromosome 21 and another chromosome. This rearrangement is called a balanced translocation because there is no extra material from chromosome 21. Although they do not have signs of Down syndrome, people who carry this type of balanced translocation are at an increased risk of having children with the condition.

 

Statistics Down Syndrome and Sickle cell anemia

There are no own statistics on the number of people with Down syndrome in Russia. From official sources in Russia, there are only data in the Russian Ministry of Health handbooks on morbidity. The compilation of the Ministry of Health of the Russian Federation "General morbidity of the whole population of Russia in 2017" shows that 18,385 people with Down syndrome were registered in the Russian Federation in 2017 

 According to WHO statistics, every 700-800th infant in the world is born with this diagnosis. The causes of the syndrome have nothing to do with environmental conditions, parental behavior, taking any medications and other negative phenomena.

The Ministry of Health told how often children with Down syndrome are born in Bashkiria. This is a genetic disease caused by changes in the number of chromosomes.

Currently there are 1,020 people with this syndrome in Bashkiria, including 709 children. On average, about 30 children with this genetic anomaly are born each year in the region, which is about 0.05% of the total number of newborns.

The Ministry of Health stresses that each year the proportion of newborns with this diagnosis decreases. Over the past decade, the birth rate in the country has almost halved.

 

Down Syndrome Disease for 2023. 

 In the Russian Federation (RF) the incidence of anemia in all age groups in 2017 was 1,123.6 cases per 100,000 population. In the Volga Federal District (VFD), which includes the Republic of Bashkortostan (RB), the overall incidence of anemia in 2017 was 1.32 times higher than the national rate and 2.3 times higher in RB

 Sickle cell anemia statistics per 100,000 people in 2023. 

 

Conclusion

The mutation process is the main source of changes leading to various pathologies. The tasks of science in the near future are defined as reducing the genetic burden by preventing or reducing the probability of mutations and eliminating the changes that have arisen in DNA with the help of genetic engineering. Genetic engineering is a new direction in molecular biology that has emerged in recent years, which may in the future turn mutations to human benefit, in particular, effectively fight viruses. Already, there are substances called antimutagens that lead to a weakening of the rate of mutation. The successes of modern genetics are used in the diagnosis, prevention and treatment of a number of hereditary pathologies. So, in 1997, recombinant DNA was obtained in the USA. Artificial genes of insulin, interferon and other substances have already been constructed with the help of genetic engineering.

 

REFERENCES:

 

  1. Principles of Genetics (2011), D. Peter Snustad, Michael J. Simmons.
  2. Books on genetics A Biologist's Guide to Analysis of DNA Microarray Data Steen Knudsen.rar
  3. The Science of Genetic and Reproductive Technologies, 2003,
  4. Genetic Modification of Hematopoietic Stem Cells. Methods and Protocols, 2009
  5. Homology Effects. Advances in Genetics, 2002
  


Полная версия статьи PDF

Номер журнала Вестник науки №5 (62) том 3

  


Ссылка для цитирования:

Izmailova L.S., Miroshnichenko A.V., Sitdikova A.I., Khammatova E.N. DOWN SYNDROME. SICKLE CELL ANEMIA // Вестник науки №5 (62) том 3. С. 867 - 876. 2023 г. ISSN 2712-8849 // Электронный ресурс: https://www.вестник-науки.рф/article/8315 (дата обращения: 28.03.2024 г.)


Альтернативная ссылка латинскими символами: vestnik-nauki.com/article/8315



Нашли грубую ошибку (плагиат, фальсифицированные данные или иные нарушения научно-издательской этики) ?
- напишите письмо в редакцию журнала: zhurnal@vestnik-nauki.com


Вестник науки СМИ ЭЛ № ФС 77 - 84401 © 2023.    16+




* В выпусках журнала могут упоминаться организации (Meta, Facebook, Instagram) в отношении которых судом принято вступившее в законную силу решение о ликвидации или запрете деятельности по основаниям, предусмотренным Федеральным законом от 25 июля 2002 года № 114-ФЗ 'О противодействии экстремистской деятельности' (далее - Федеральный закон 'О противодействии экстремистской деятельности'), или об организации, включенной в опубликованный единый федеральный список организаций, в том числе иностранных и международных организаций, признанных в соответствии с законодательством Российской Федерации террористическими, без указания на то, что соответствующее общественное объединение или иная организация ликвидированы или их деятельность запрещена.