Which are the causes of Down Syndrome?

Down Syndrome:

Down Syndrome, also known as Trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. It is the most common chromosomal abnormality in humans, occurring in approximately 1 in every 700 births. The condition leads to various physical and intellectual disabilities, but with proper support and care, individuals with Down Syndrome can lead fulfilling lives.

Causes of Down Syndrome:

Down Syndrome is primarily caused by a random error in cell division during the formation of reproductive cells (eggs and sperm) in one of the parents. This error, known as nondisjunction, results in an extra copy of chromosome 21. The exact reason behind this error is still unknown, but several risk factors have been identified:

1. Advanced Maternal Age: The risk of having a child with Down Syndrome increases with the age of the mother. While the majority of babies with Down Syndrome are born to women under the age of 35, the likelihood significantly rises after the age of 35 and continues to increase with each subsequent pregnancy.



2. Translocation: In some cases, Down Syndrome is caused by a rearrangement of genetic material between chromosome 21 and another chromosome. This is known as translocation. It can occur spontaneously or be inherited from a parent who carries a balanced translocation, where the extra chromosome 21 attaches to another chromosome instead of existing as a separate chromosome.



3. Mosaic Down Syndrome: This is a rare form of Down Syndrome where only some cells in the body have an extra copy of chromosome 21. Mosaic Down Syndrome occurs when nondisjunction happens after fertilization, leading to a mixture of cells with the normal number of chromosomes and cells with an extra copy of chromosome 21.

Effects of Down Syndrome:

Down Syndrome affects individuals in various ways, both physically and intellectually. Some common physical characteristics include low muscle tone, upward slanting eyes, a flat facial profile, a small nose, and a single deep crease across the center of the palm. Individuals with Down Syndrome may also experience certain health conditions at a higher frequency, such as heart defects, hearing loss, vision problems, and thyroid disorders.

Intellectual development is typically delayed in individuals with Down Syndrome. They may have mild to moderate intellectual disabilities, but the range of abilities can vary widely. Early intervention, educational support, and therapies can greatly enhance their cognitive and social development.

Conclusion:

Down Syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21. While the exact cause of the chromosomal error is not fully understood, advanced maternal age and translocation are known risk factors. The condition leads to various physical and intellectual disabilities, but with appropriate care and support, individuals with Down Syndrome can lead fulfilling lives and make valuable contributions to society.