Down syndrome is a genetic disorder or chromosomal disorder caused due to abnormal cell division (aneuploidy of autosome) generally Human cells contain 23 pairs of chromosomes. One chromosome in each pair comes from your father, the other from your mother. In downs syndrome aneuploidy of autosome occurs which results in part of chromosome or extra copy of chromosome 21 in all cells or some cells. This extra genetic material causes the developmental changes in the baby causing physical features of Down syndrome which is also known as trisomy 21.
The occurrence of Down syndrome is 1: 800 live births. It accounts to around 30000-35000 child born in india every year.Down’s syndrome or faulty chromosome is formed during conception when the genetic bundles from the ovum and sperm fuse to form zygote. caused due to abnormal cell division generally, during mitotic and meiotic cell division the chromosome pair separate so that each cell gets a copy of each chromosome. In down syndrome, the chromosomes are not able to separate, giving rise to cells with an unequal number of chromosomes. This Is called nondisjunction.it happens when chromosome segregates in anaphase before all of the replicated chromosomes’ kinetochores are attached to microtubules from opposite poles during metaphase. It results in one daughter cell having one less chromosome and another with one extra chromosome.
Down syndrome is also due to the translocation of a part of a chromosome to another chromosome. The number of chromosomes is normal but one chromosome has an extra part of chromosome 21.
There is no exact information got for the genes missing in these individuals but the extra copy of genes of chromosome 21 causes abnormal physical and mental development. Few researches have informed that any kind of trauma to mother or child during pregnancy. Any prior treatments taken for fertility can also cause trisomy 21.DS is mostly not inherited. Translocation Down syndrome can be passed from parent to child. It might be hidden in the parent due to balanced translocation with no symptoms but can pass the unbalanced translocation to the child and cause Down syndrome.
Down syndrome varies in severity among individuals causing lifelong intellectual disability and developmental delay in an individual. Downs syndrome is the most common genetic chromosomal disorder and causing learning disabilities in children as well as physical developmental delay in a
child. We need early intervention which can greatly increase the quality of life for children and adults with this disorder and help them live fulfilling lives.
Symptoms
People with down syndrome can be easily identified by their physical attributes and facial features. Slowly after birth different symptoms start appearing. Infants may be of normal size but as they grow slowly, their height gets affected. Infants with Down syndrome may be average size, but typically they grow slowly and remain shorter than other children the same age.
Each person with Down syndrome is an individual intellectual and developmental problems may be mild, moderate or severe. Some people are healthy while most of them have significant heart and brain related issues along with physical and developmental problems.
