Understanding Down Syndrome: Causes, Types, And Impacts

Causes and Types of Down Syndrome

Question:

Discuss about the Down syndrome is a chromosomal disorder.

Down syndrome is a chromosomal disorder caused due to the abnormal division of cells which leads to an extra full or partial copy of chromosome 21 (Sherman et al, 2007). ‘Jerome Lejeune’, a French physician, developed the cause of down syndrome in 1959 (National Down Syndrome Society). In case of down syndrome, the count of chromosomes is 47 instead of 46 (half chromosomes comes from the mother and half from the father i.e. 23 from each). So this is due to having one extra chromosome number 21 in addition to the already existing normal pair. This type of down syndrome is called trisomy 21 which accounts for 95% of the down syndrome cases (Spencer, 2014). According to researchers the extra copy of chromosome 21 affects the normal course of development of an individual, and also there is an increased risk of health problems associated with this disorder (Dekker, De Deyn, & Rots, 2017).

Mosaicism is the least common form of down syndrome which accounts for only one percent of cases. This occurs due to a mixture of two type of cells, with some containing the usual count of 46 and some containing 47 chromosomes. People suffering from mosaic down syndrome have very fewer characteristics as compared to other types of down syndrome). Translocation type of down syndrome accounts for the remaining 4% cases of the down syndrome. In this type the additional full or partial copy of chromosome 21 attaches to the another chromosome (chromosome 14) (Dekker, De Deyn, & Rots, 2017). The hereditary component is present only in one third cases of translocation down syndrome, that accounts for one percent of the total cases of down syndrome as a whole. This genetic disorder further affects the physical and mental wellbeing of the individual by slowing the development growth both physically and mentally.

 An individual with down syndrome may also suffer from heart and gastrointestinal disorders. Early interventions and better knowledge about down syndrome will greatly help in increasing the quality of life of the children or adult facing this disorder (Centre for Arab Genomic Studies, 2013). Small stature, low muscle tone, an upward slant to the eyes and a single deep crease across the center of the palm are some of the physical changes that are rightly noticeable in an individual facing this disorder (Dekker, De Deyn, & Rots, 2017). However, these are not necessarily the only physical changes that an individual face. Language development is also very slow amongst the children facing this disorder.

The study of Aburawi, et al, (2015) also finds that children suffering with down syndrome are significantly shorter and heavier in weight than normal children. Obesity is also a significant problem among such children. There can be behavioral issues also like attention problem, stubborn nature, obsessive and compulsive behavior etc. Autism spectrum disorder is also found in a very small percentage of people facing this disorder which affects communication and social interaction (Dekker, De Deyn, & Rots, 2017). A gradual decline in thinking ability is also seen among the people with down syndrome as they age.

Impacts of Down Syndrome on Physical and Mental Growth

Down syndrome is considered as the most common congenital anomalies that is affecting 1 in every 800 births. An individual with down syndrome may have a full extra or partial part of chromosome 21 present. However, the cause of this extra full or partial chromosome 21 is still unknown. The prevalence of down syndrome differs from country to country because of the various social and environmental factors. For, example the incidence of down syndrome may be lower in the developed countries, in comparison to developing countries. This could be because the developed countries in the Arab world may have better application and uptake of the antenatal diagnostic service and also receives the permission to terminate the pregnancy if such case is discovered. According to the study of Al-Biltagi (2015) “the estimated incidence of down syndrome is between 1 to 10/1000 live births worldwide” (p. 85).

The only factor linked to an increased chance of having a baby with down syndrome is the maternal age (National Down Syndrome Society, 2016) and the risk increases with an increase in maternal age. According to a report the risk is 1:1000 at the age of 30 while at the age of 35 the risk is 1:400 (Centre for Arab Genomic Studies, 2013). According to a report the incidence of down syndrome in some Arab countries is slightly higher as compared to the other countries globally. The incidence of down syndrome in Dubai is 1:319, in Oman it is 1:500, Qatar (1:546), Saudi Arabia (1:554), Kuwait (1:581), Israel is 1:547 (Al-Biltagi, 2015). There are a number of factors associated with the higher number of incidence rate in Arab countries such as consanguineous marriages (marriages among first cousins), increased maternal age and having a high number of children, lack of prenatal detection which further to terminate pregnancies with down syndrome fetuses (Hamamy et al, 2011).

People with Down syndrome often take some drugs and supplements to support their brain activities but according to a research the medicines are not able to make any specific change or there are no medicines developed till date that helps a person to recover from this disorder. The burden of this disease is very high in Arab world, because it results in significant morbidity, mortality and disability among the infants. The rate of children suffering with down syndrome in many Arab countries is increasing from 1.2-1.7 per 1000 mainly in the industrialized countries. This mainly due to the high proportion of the child birth. Having large number of children is a traditional and cultural element in the Arab world and they prefer having many children in family. This is a significant risk factor, as the mothers keeping giving birth to children till very old age that affects the health and well-being of the children being born in older age of mother.

There are various social and economic trends associated with a high maternal age in the Arab world. This is due to the fact that most of the women in the Arab world choose high level of professional development in the early 20s and the early 30s (Al-Biltagi, 2015). The only reason associated with it is to provide better financial conditions to the family for a healthy living. So now the Arab world is also experiencing similar trends as that of the western world throughout the shift to industrialization, so there is a need to take the same measures or to adopt the same practices as that of the western world like antenatal screening using ultrasounds, amniocentesis and chronic villus sampling as well as preserving the oocyte (an egg bank) (Acikbas et al, 2012). This results in creating a significant burden of the disease. The high prevalence of down syndrome in Arabs is due to their socio-economic and religious belief that includes the common practice of consanguineous marriages, multiparty and increased maternal age.

Risk Factors Associated with Down Syndrome in Arab Populations

Lack of educational awareness can also affect the prevalence and incidence of down syndrome. The lack of education also affects the health outcome of the people in Arab world. The people, who are not educated, do not understand the significance of the antenatal screening tests, which is significant for detecting the down syndrome in the babies (Korayem, & AlKofide, 2013). Therefore, lack of knowledge and education of the parents also prevents them from taking antenatal screening and terminating such pregnancies. The people in Arab world are at the risk of genetic problem even if they have the family history of genetic disorder or not. Various countries in Arab world have also made the provisions for the premarital screening and antenatal screening. However, the poor access of people to such programs and facilities results in increasing the burden of disease (Al-Gazali, Hamamy, & Al-Arrayad, 2006).

The children suffering from down syndrome have different physical features, physical structure and also have language problems. Such children may face many difficulties in social interaction and may not get appropriate opportunity of social inclusion (Al-Kindi, Al-Juhaishi, & Al-Saffar, 2012). Studies have found that there is a lack of awareness among the people towards the individuals suffering from down syndrome and this may result in discriminatory behavior towards them. The burden of the disease on the patients and families’ increases, due to the problem of stigmatization and social exclusion. Perception of the people towards down syndrome has been found to be very poor (Al-Kindi, Al-Juhaishi, & Al-Saffar, 2012). People often hold negative opinion and negative attitude about people suffering from down syndrome. This can also result in many psychological consequences and can increase the burden of the disease Al-Biltagi, (2015). However, there is a lack of qualitative and quantitative evidences of the community attitude and attitude of people in Arab World. Although, it has been found that parents do have positive attitude towards the social inclusion of their children in schools, yet, in general, people in Arabian countries lack the awareness towards the intellectual disability disorders.

Aim of the review is to provide significant and important evidences found in the literature. The search for the articles is conducted through PubMed also some of the articles are also added from the cross reference and other important journals. Down syndrome is a common congenital anomaly in Saudi Arabia. The frequency of such anomalies differ from country to country on the basis of various factors. Although, there have been decrease in the prevalence of such disease with the increasing technological advancement and treatment range, yet Down syndrome still significantly prevails and result in significant childhood mortality. Therefore, it has also been found that genetic disorder causes significant morbidity, mortality and disability among children in Middle East. Genetic disorder is the major problem in the Arab world. This review is mainly focused on discussing the current knowledge and understanding about the genetic disorders, such as down syndrome and its prevalence in Arab World.

The inclusion criteria that has been applied for the research is that only published studies and government reports are select for the purpose of this review. This inclusion criterion is applied in order to maintain the quality of the evidences. PubMed is specifically used to locate the articles, cross-sectional studies and quantitative studies for preparing this review. The statistically significant results can be appropriately obtained from the quantitative study. Therefore, the review has focused on finding and locating the appropriate and current studies that could provide the current rate of prevalence, incidence and effects of Down Syndrome in Arab World. Therefore, this review aims towards providing the effective and readable synthesis of the quality resources and could also help in enhancing the knowledge about the current area of research. The review also provides the directions for the future research in reference to down syndrome and its effect on population in Arab World.

The qualitative method and inductive approach has been used in preparing this review. Keyword research method have been used for locating the resources in PubMed. Some of the keywords that are used for locating the appropriate resources are ‘Down syndrome’, ‘what is down syndrome’, ‘prevalence of down syndrome’, ‘risks associated with down syndrome’, ‘burden of down syndrome on population’, ‘incidence of down syndrome in Arab World’, ‘risk factors and down syndrome’, ‘prevalence of down syndrome in Arab World’ and ‘reasons of down syndrome prevalence’.

Methodology is a very important approach for preparing the research articles and research studies. The key word search requires to enter the correct keywords and must be in line with the requirements and objectives of the study. The main objective of the study to provide the review of literature in order to find the evidences that can help in developing knowledge about the current scope and disease prevalence.

This study is found to be significant because it provides important and current evidences related to down syndrome. The study also defines the genetic disorder, however, it lacks to provide the empirical evidences about the epidemiology of the down syndrome. This study can be beneficial in exploring the epigenetics associated with down syndrome.

This is a very important study as it is focused on the Arab country and can help in informing about prevalence and epidemiology of down syndrome. UAE is a significant part of Arab World and a developed country. The prevalence of disease in this country provides a strong in sight about the reasons of disease occurrence and also inform that what challenges children have to face, who are suffering from down syndrome. This article helped in gaining the epidemiological information about disease.

This study has been helpful in informing about the incidence and prevalence of down syndrome around the world. This study provides some strong evidences about the epidemiology of this genetic disorder and what are the major risk factors associated with it. However, the study lacks some significant empirical evidences. Study identifies down syndrome as the most common genetic disorder globally. One significant limitation of the study is that it provides the evidences from the sample of children from United States.

This study is significant because it informs about the antenatal screening, which is significant for identifying the genetic disorder in babies. Screening is considered as the important and successfully developed as the biochemical marker and algorithms for identifying the risks mainly associated with trisomy 21 and 18. This study is very significant for increasing the awareness towards the process of screening that is mainly important in the Arab world, because the incidence of down syndrome in children is higher in Arab countries.

This is a document that significantly address the issue of down syndrome in relation to Arab World. One significant limitation of the study is that it is not a journal article or papers, yet is associated with Arab Genomics, therefore, provides many significant evidence mainly associated with Arab countries. It provides the information about prevalence and incidence rate. The only limitation of the study is that it lacks empirical evidences from literature.

The study discusses a very significant risk factor that results in high occurrence of down syndrome around the world. Study discusses the Consanguineous marriages as the significant risk factor for the occurrence of genetic disorder including down syndrome. This study is included in the research because Consanguineous marriages are customary and common in Arab World ad a significant reason of occurrence of down syndrome.

This study is considered to be very important because its views the genetic disorder from the epidemiological perspective. It provides the prevalence data related to down syndrome in Arab world and also in many other countries. The limitation of the study is that it lacks empirical data. However, it also identifies the genetic and environmental factors that can result in causing down syndrome in children. However, study consider maternal age as an risk factor in occurrence of down syndrome.

This study is conducted in Turkey, which is also a Muslim natation and also follows the traditions and belief according to people in Arab World. The author informs that down syndrome is the most common chromosome abnormality among the live births. Maternal age and lack of antenatal screening are considered as major risk factor. The study is a cross sectional study and provide empirical evidences.

This study informs about the gap in literature, as very limited evidences are available on the prevalence of the congenital anomalies in Middle East countries. This cross sectional study informs that prevalence of congenital anomalies in Saudi Arabian children is high because of the high consanguinity rate and high maternal age. This study is also important because it is community based and provide empirical evidences regarding the prevalence, incidence, risk factors and gaps in knowledge.

This study compares the main characteristics of the individuals suffering from down syndrome with the normal subjects with the help of cephalometric radiographs. This study can be help in directing the future research regarding the treatment of individuals suffering with down syndrome. This study defines the down syndrome, however, lack data regarding the incidence and prevalence of the disease.

This study is mainly focused on the prevalence and incidence of genetic disorder in Arab World. This study identifies the major risk factors such as high level of inbreeding, high maternal and paternal age and also large family sizes. This study found that there are various factors affecting the knowledge of people about disease. Therefore, it required that focus should be placed on enhancing knowledge and education of people and also improve the access of people to specialized genetic services.

This study is very significant because it informs about the attitude of the people towards the individuals suffering from down syndrome. It explains about the burden of the disease on the people and their families. These evidences are important in order to design the future interventions for improving the life of people suffering with down syndrome in Arab nations.

Down syndrome is considered and found to be the most common genetic disorder in the Arab World. The findings of the paper inform about various reasons that increases the risk of this genetic disorder in children. The findings of the study inform that some of the major reasons behind prevalence of this disorder are Consanguineous marriages, traditional and religious custom of marrying the first cousins, high maternal age and also multiparty. There are various genetic, environmental and social factors that can increase the prevalence of this disorder. Study found that antenatal screening is very helpful in finding the genetic disorder in the fetus and after knowing parents can terminate the pregnancy. However, due to religious and social restrictions and also due to economic and ethnic factors, abortion is not allowed and women have to give birth to children, even after knowing that child suffers from genetic disorder and will not be able to lead a normal life.

In comparison to evidences from France and Europe, it has been found that abortion is allowed in France and Europe, therefore, the birth prevalence of down syndrome is reduced in these countries. For example, it was found that incidence rate of down syndrome in live births in Dubai is 1:319, it is 1:500 in Oman, 1:554 in Saudi Arabia, and 1 in 700 in Egypt in Egypt, while the incidence rate in China is 2/1000, 0.83/1000 in India and it is 1:1700 in Australia (due to high termination rate). Therefore, the above data informs that prevalence and incidence rate is higher in Arab countries. There are various reasons identified for high incidence and prevalence. One of the religious or cultural reason is that Arab people believe in making large families and giving birth to many children. Giving birth to many children through Consanguineous marriages affects the chromosomes and results in creating genetic anomalies. Also one reasons are that mother keep giving birth to children even after the age of 40 and age is a significant risk factor.

Therefore, maternal age affects the health and well-being of the children. Due to contemporary changes in the culture and society, one reason is that women are also now taking an active part in economy. Women are participating in receiving higher education and are making careers. This restricts them to give birth to children in early or appropriate age. Also, in many part of the Arab world, the population is still tribal and are uneducated. Therefore, they lack the significance of understanding the disease, disadvantages of giving birth to many children and understanding the importance of antenatal screening. The hereditary problems and genetic disorder in the tribal people increases the overall burden of the disease. Also, it has been found that 50% of the children that are born with the down syndrome disorder are born to mothers, who are 40 years or above in age.

There is a significant gap in the literature, regarding the prevalence and major risk factors associated with it.  It has also been found that there is a lack of extensive healthcare programs, campaigns and interventions that could encourage women more towards antenatal and premarital screening about chromosomal abnormality. The nation where the risk is higher and as it is scientifically proved, it becomes very significant to increase the awareness of people. There is also a lack of healthcare counselling that could be provides to the couples, in order to enhance their knowledge about this genetic disorder. Therefore, there is a significant loop hole on policy level.

Another problem is identified on the social and legal level. For example, termination of pregnancy is not legally and religious allowed in the Arab countries, even when a ruling in 1990 allowed the termination of pregnancy in the first 120days, if the fetus was found to be significantly affected by sever malformation that could not be even improved after the treatment. However, people are still restricted from terminating pregnancy. Therefore, there is requirement of making a strong law and policy that could address such problem and may also help in reducing the prevalence of down syndrome in Arab countries. A family oriented approach is required to be designed and applied that could help in informing people about the risks of giving birth to large number of children and how proper screening approaches can benefit them in having healthy children. Also, the clinical screening of the new born can help the clinicians in detecting the abnormalities. This way parents could be better prepared to take care of such children and provide them better environment. Increasing the awareness of parents and people in community can help in better inclusion of such children in community.

References 

Standard Journal Articles

Acikbas, I., Tomatir, A. G., Akdag, B., & Koksal, A. (2012). Retrospective analysis of live birth prevalence of children with Down syndrome in Denizli, Turkey. Genet Mol Res, 11(4), 4640-5.

Aburawi, E. H., Nagelkerke, N., Deeb, A., Abdulla, S., & Abdulrazzaq, Y. M. (2015). National growth charts for United Arab Emirates children with Down syndrome from birth to 15 years of age. Journal of epidemiology, 25(1), 20-29.

Al-Biltagi, M. (2015). Down syndrome from Epidemiologic Point of View. EC Paediatrics, 2, 82-91. (PubMed)

Al-Gazali, L., Hamamy, H., & Al-Arrayad, S. (2006). Genetic disorders in the Arab world. Bmj, 333(7573), 831-834.(PubMed)

Al-Kindi, S. G., Al-Juhaishi, T., & Al-Saffar, A. J. (2012). Community attitudes towards people with down’s syndrome: A sample from Iraq. Public Health Research, 2(4), 102-105.

AlSalloum, A., ElMouzan, M. I., AlHerbish, A., AlOmer, A., & Qurashib, M. (2015). Prevalence of selected congenital anomalies in Saudi children: a community-based study. Annals of Saudi medicine, 35(2). (PubMed)

Dekker, A. D., De Deyn, P. P., & Rots, M. G. (2017). Epigenetics and Down syndrome. In Neuropsychiatric Disorders and Epigenetics (pp. 163-184).

Hamamy, H., Antonarakis, S. E., Cavalli-Sforza, L. L., Temtamy, S., Romeo, G., Ten Kate, L. P., ... & Bathija, H. (2011). Consanguineous marriages, pearls and perils: Geneva international consanguinity workshop report. Genetics in Medicine, 13(9), 841. (PubMed)

Korayem, M. A., & AlKofide, E. A. (2013). Characteristics of Down syndrome subjects in a Saudi sample. The Angle Orthodontist, 84(1), 30-37. (PubMed)

Sherman, S. L., Allen, E. G., Bean, L. H., & Freeman, S. B. (2007). Epidemiology of Down syndrome. Developmental Disabilities Research Reviews, 13(3), 221-227. (PubMed)

Spencer, K. (2014). Screening for Down syndrome. Scandinavian Journal of Clinical and Laboratory Investigation, 74(sup244), 41-47. (PubMed)

Electronic Material

Centre for Arab Genomic Studies. (2013). Down Syndrome in the Arab world. Retrieved from https://www.cags.org.ae/Down%20Syndrome-English.pdf