Introduction
Trisomy 18 (also referred to as Edwards Syndrome) is a rare genetic disorder (Gilmore, 2009). It occurs when part of an individual’s chromosome 18 is duplicated. This causes the development of a third copy of chromosome 18. This genetic error usually occurs as a result of nondisjunction during the meiotic stage. As the name suggests, it was first coined by John Hilton Edwards. He described it in 1960.
This syndrome is among the most common type of Trisomy. It comes second after Down syndrome. Only one in about 6,000 cases survives to birth. Another statistic indicates that about 80% of the affected are female. The largest proportion of individuals with the condition dies even before birth. For those who survive to birth, most die within one month after birth. Another small proportion may survive for about one year.
However, a few individuals may survive past the first year after birth. However, such individuals usually require appropriate treatment due to the various adverse effects associated with the condition. Older women are at high risk of conceiving such children. Those of ages 30 and above have a greater risk.
Edwards syndrome manifests itself in several ways and affects the individual’s external and internal organs. Individuals with this syndrome have abnormally formed toes and fingers. Abnormalities are also seen in the way the ears, mouth, lips, and head are developed.
Internal organs such as muscles, lungs, heart, and blood vessels are also abnormally developed. Apart from appearance, the cognitive abilities of children are affected. Learning is also greatly impaired since these individuals have psychiatric issues.
Causes
A normal human gene contains 23 pairs of chromosomes numbered 1 to 22. The 23rd pair usually contains the X-chromosome and Y-chromosome. A newborn inherits a set of 23 chromosomes from either of the parents. In rare occasions, a genetic error may occur during the development of the sperm cell or the ovum. When the offspring is conceived with either of these cells, it may inherit a different number of chromosomes.
In the case of Trisomy 18, the newborn inherits an additional chromosome. As a result, three copies of the chromosome appear. This may occur in different forms. Most of the children with this disorder are full trisomies. A small percentage of individuals are mosaic trisomies (Banka, Metcalfe, & Clayton-Smith, 2013).
Such individuals have the extra chromosome appearing in only some of the cells. Other cases are due to translocations. In such a case, only a portion of the extra chromosome appears. These cases are usually hereditary.
Consequences
Trisomy 18 is usually fatal. Most babies with this condition die even before birth. Thirty percent of the newborns die within the same month. Very few live long enough to celebrate their first birthday. Edwards syndrome manifests itself in various ways. The manifestations may be external or internal. Most babies with the syndrome appear weak. They are also usually underweight. The babies may also have abnormally small heads.
The ears may show malformation and are usually low-set. The mouth and jaws of such children are usually small. Some develop cleft lips. The hands of the babies with the conditions are abnormally formed since they tend to clench into fists. Many have overlapping fingers. Some develop clubfeet with toes that are fused or webbed.
Apart from external abnormalities, babies with Edwards Syndrome may also develop malformed internal body organs. For example, the lungs and diaphragm may be abnormally developed. In most occasions, the blood vessels of such individuals may be malformed.
Several congenital heart diseases may also develop in such individuals. Examples include Atrial Septic Defect and Ventricular Septal Defect. Male individuals may have abnormally formed urogenital systems. Others have malformed kidneys. Another consequence of the condition may be manifested in the form of inguinal and umbilical hernia.
Due to issues with muscle tone and abnormalities with the nervous system, the motor skills of such individuals may be affected (Baty, Jorde, & Blackburn, Carey, 1994). This could lead to curvature of the spine. This condition is also referred to as scoliosis. Due to the same problem, esotropia may develop.
This is the case whereby the eyes appear crossed. What makes things worse is the fact that medical interventions, such as surgeries may be impossible to use due to issues with cardiac health. Constipation may be a life-long issue for an individual with Edwards Syndrome. This is solely due to the poor abdominal muscle tone. This is usually a source of discomfort, distress, and may cause feeding problems.
For this reason, treatment is recommended for this issue. Examples of remedies include the use of special milk formulas and stool softening medication. However, enema is strongly discouraged because it may alter fluid body composition. Individuals with Trisomy 18 may also show severe developmental delays. However, early intervention may be used to help the child attain developmental milestones.
Persons with the syndrome also have increased risks of developing cancer of the kidney. This disease is referred to as Wilms’ tumor. It mainly affects children, and it is for this reason that individuals with Trisomy 18 should have examinations of the abdominal cavity more often. Other complications, such as high blood pressure, pneumonia, seizures, ear and eye infections, pulmonary hypertension, and heart disease may occur.
Another consequence of Edwards Syndrome is the inability to feed properly. Difficulties are also experienced when breathing, swallowing, and sucking. Such children may have problems coordinating their swallow. For this reason, they may choke or vomit. Other issues may include gastroesophageal reflux disease and aspiration.
These describe the situation whereby food moves from the stomach to the throat and whereby liquid material is breathed into the lungs, respectively. Oral-facial clefts also cause issues as the child tries to feed.
How Edwards Syndrome Affects Learning Process
Children with Edwards Syndrome usually have learning problems due to the affected nervous system and brain. Mental retardation usually results in delayed development (Gilmore, 2014).
The self-determination theory shows the importance of individuals’ innate psychological needs that influence their motivation and personality integration (Ryan & Deci, 2000). These are required to ensure constructive social development. Retardation in individuals with Edwards syndrome may affect this ability (Anderson, Lytton, & Romney, 1986).
Learning how to walk may prove to be a learning issue for individuals. For this reason, a child who has survived past the first birthday would require to use walking support. Such children also have limited verbal communication abilities (Liang, Braddock, Heithaus, Christensen, & Carey, 2013). However, such children may respond to cuddling and may smile and interact with the guardian (Carey, 2012).
Response to stimuli such as cuddling indicates development since the Behavioural Child Development Theories propose that development is indicated by the child’s reaction to stimuli, punishment, and reinforcements (Dunn, 1992).
According to the Group Socialization Theory proposed by Harris (1995), parents, teachers, and other members of society play an important role in the child’s learning process. Children with Edwards syndrome should have special education needs.
Individuals with Edwards syndrome have difficulties expressing themselves using words (McGraw & Perlman, 2008). Liang, Braddock, Heithaus, Christensen, and Carey (2013) conducted a study to investigate the communication ability of individuals with Edwards syndrome. According to the Sensory Stimulation Theory, effective learning takes place when there is a stimulation of the senses.
These senses include sight and hearing. The individuals with Edwards syndrome can learn by watching and hearing. This is consistent with the cognitive Child Development Theory by Piaget, which proposes that a child actively gains knowledge from the environment.
Conclusion
Edwards syndrome is a genetic disorder that alters chromosome composition. The additional chromosome may cause death in most of the babies. Most die before birth, and many more die within the first month. For those that survive past the first year develop many abnormalities.
Some defects would be visible on the outside, but some occur internally. Such children also experience learning problems since their nervous systems and brains are affected. Although these children may show some form of communication using gestures or body language, they are unable to speak sensibly (Nicoladis, Mayberry, & Genesee, 1999).
References
Anderson, K., Lytton, H., & Romney, D. (1986). Mothers’ interactions with normal and conduct-disordered boys: Who affects whom? Developmental Psychology, 22(1), 604-609.
Banka, S., Metcalfe, K., & Clayton-Smith, J. (2013). Trisomy 18 mosaicism: Report of two cases. World J Pediatr, 9(2), 179-181.
Baty, B., Jorde, L., & Blackburn, B., Carey, J. (1994). Natural history of trisomy 18 and trisomy 13: Psychomotor development. American Journal of Medical Genetics, 49(1), 189–184.
Carey, J. (2012). Perspectives on the care and management of infants with trisomy 18 and 13: Striving for balance. Current Opinion in Paediatrics, 24(1), 672–678.
Dunn, J. (1992). Siblings and development. Current Directions in Psychological Science, 1(1), 6-9.
Gilmore, L. (2014). Understanding chromosome disorders and their implications for special educators. Cypriot Journal of Educational Science, 9(1), 14-20.
Gilmore, L. (2009). Rare chromosome disorders and their developmental consequences. Intellectual Disability Australasia, 30(1), 3-7.
Harris, J. (1995). Where is the child’s environment? A group socialization theory of development. Psychological Review, 102(3), 458-489.
Liang, C., Braddock, A., Heithaus, J., Christensen, K., & Carey, J. (2013). Reported communication ability of persons with Trisomy 18 and Trisomy 13. Dev Neurorehabil, 1751(8423), 1-8.
McGraw M., & Perlman, J. (2008). Attitudes of neonatologists toward delivery room management of confirmed Trisomy 18: Potential factors influencing a changing dynamic. Paediatrics, 121(1), 1106–1110.
Nicoladis, E., Mayberry, R., & Genesee, F. (1999). Gesture and early bilingual development. Developmental Psychology, 35(1), 514–526.
Ryan, R., & Deci, E. (2000). Self-determination theory and the facilitation of intrinsic motivation, social development, and well-being. American Psychologist, 55(1), 68-78.