Introduction
Down’s Syndrome is another type of genetic disorder that is caused due to the existence of an extra chromosome. It is also known as the name of Trisomy of chromosome 21. It is the most popular and common genetic disorder all around the world. More than 90% of genetic disorders worldwide are Down’s Syndrome. This condition was first observed by the physician Langdon Down, which is why it is named Down’s Syndrome.
Down’s Syndrome causes not only mental retardation or physical attributes but also causes various diseases like Alzheimer’s or leukemia. It may be diagnosed in the process of screening in pregnancy at an early stage and can lessen the happening of the Syndrome.
Down’s Syndrome Cause
- Down’s Syndrome is caused due to the presence of an extra autosome that causes the chromosomal disorder. In Down’s Syndrome, part of the chromosome or one extra chromosome 21 is present in some cells or all cells.
- The cases of Down’s Syndrome are 1 out of 700 live births. One of the significant causes of Down’s Syndrome is the mother’s age. More than 35 years of a mother’s age is the reason for most trisomy cases in the world.
- It happens because of abnormal cell division during meiotic and mitotic cell division; the pair of chromosomes get separated so that each cell gets a copy of each chromosome. In this syndrome, the chromosomes are not capable of getting separated and cause the rise of cells with a different number of chromosomes and named non-disjunction.
- Down syndrome happens because of the relocation of a part of a chromosome to another chromosome as well. The sum of chromosomes in the cells is normal, but one chromosome contains an extra part of chromosome 21. It does not create a loss of genetic information in these babies but having an extra copy of genes of chromosome 21 causes not normal mental and physical development in the individuals.
- Down’s Syndrome can not be inherited, but in the cases of translocation Down’s Syndrome, it can be passed on from the parent to the baby. It may be concealed in the mother or father due to equalized translocation without any symptoms but can be passed on to the infant and generate Down’s Syndrome.
Down’s Syndrome classification
Down’s Syndrome is classified into three categories: Trisomy 21, Mosaicism, and Translocation Down’s Syndrome. Let us discuss them briefly:
- Trisomy of 21: Trisomy is the most commonly seen category of Down syndrome, and 95 per cent of cases of Down syndrome are caused by this kind. There is one extra chromosome, 21, present in the cell, i.e. rather than the usual 46 chromosomes, the total number of chromosomes present is 47.
- Mosaicism: mosaicism is the not-so-common form of Down’s Syndrome, and 1% of the total cases of Down syndrome are caused by this kind.
- Translocation Down’s Syndrome: This kind of Down’s Syndrome is also rare, and 4 percent of the total cases of Down syndrome are caused by this kind.
In this type of Down’s Syndrome, an extra chromosome 21 does not exist, but there is an extra part in the chromosome 21 present attached to another chromosome, i.e. one chromosome is abnormal out of 46 chromosomes.
It is caused because of the translocation of the q arm of chromosome 21 to another chromosome in the process of replication. It is then translocated to chromosome 14. A person that has translocation Down syndrome has one chromosome 14. This event is not associated with the age of the mother, and it can be inherited.
Down Syndrome Symptoms
- People that have Down’s Syndrome are born with several abnormalities. They are seen to have mental and physical disabilities. They have bad immunity and are likely to catch many infections. They attain milestones that are developmental at an older age than the normal age. In many cases, individuals are born with thyroid disease, congenital heart defects, gastrointestinal defects, and sleep apnea. They have increased vulnerability to diseases like Alzheimer’s and leukemia.
- Individuals suffering from down syndrome can be recognized easily by their physical characteristics and facial details. After they are born, they start to show different symptoms slowly. Newborns might be of the size that is normal, but as they grow, their height increases lesser than those of a similar age.
The primary symptoms of Down’s Syndrome are as follows:
- Mental retardation
- Cognitive impairment may be mild to moderate
- Tilted eyes or Fold of the skin above the eye
- Cardiac weaknesses
- Excessive flexibility and poor muscle tone
- A hand is wide and short or single transverse palmar crease
- Hinder in language development
- Stunted development and short stature
- Flattened nose and protruding furrowed tongue
- Short neck, small head, and unusual teeth
Down’s Syndrome treatment
It cannot be cured. Early therapy programs can help improve skills. With support and therapy, many people with Down syndrome can live productive and happy lives. Some of the therapies for Down’s Syndrome are as follows:
- Occupational Therapy
- Physical Therapy
- Special Education
- Speech-language Therapy
- Assistive Technology
Conclusion
In this article, we have discussed Down’s Syndrome, its definition, causes, symptoms, and treatment. We also saw that it is a genetic disorder and can not be inherited, but in some cases, it can be transferred from parent to child.