Types of mutation

Types of mutation. Mariam abotaleb.

What types of mutation are there?. There are lots of different mutations that can occur in our DNA. Small-scale mutations: Point mutation – a change in one base in the DNA sequence..

Substitution – when one or more bases in the sequence is replaced by the same number of bases (for example, a cytosine substituted for an adenine)..

Inversion – when a segment of a chromosome is reversed end to end.

Deletion – when a base is deleted from the sequence..

What are common genetic disorder ?.

There are many types. They include: Chromosomal disorders Down syndrome (Trisomy 21). FragileX syndrome. Klinefelter syndrome. Triple-X syndrome. Turner syndrome. Trisomy 18. Trisomy 13..

Now we will talk about down syndrome Down syndrome, the most common chromosome-related genetic condition in the U.S., affects development of the brain and body. People with Down syndrome face physical and mental challenges, but can lead full and happy lives..

What is Down Syndrome? People with Down syndrome are born with an extra chromosome, which changes the way their brain and body develop. Down syndrome is a genetic disorder. Most babies are born with 23 pairs of chromosomes within each cell for a total of 46. A chromosome is a structure that contains genes, which are made up of your DNA. Genes determine how you form and develop growing in the womb and after birth. The majority of babies with Down syndrome are born with an extra copy of chromosome 21, with three copies of the chromosome instead of the usual two..

As a result people born with Down syndrome face some physical and mental challenges throughout life. They typically have distinctive body and facial features that set them apart. They are more likely to develop slowly, and are more at risk for some medical conditions..

Are there different types of Down syndrome?.

Yes, there are three types of Down syndrome. They are: Trisomy 21: The term “trisomy” means having an extra copy of a chromosome. The most common type of Down syndrome, trisomy 21, occurs when a developing baby has three copies of chromosome 21 in every cell instead of the typical two copies. This type makes up 95% of the cases. Translocation: In this type of Down syndrome, there is an extra full or partial amount of chromosome 21 attached to another chromosome. Translocation accounts for 4% of the cases. Mosaicism: In the rarest type (only 1%) of Down syndrome, some cells contain the usual 46 chromosomes, and some contain 47. The extra chromosome in these cases is chromosome 21..

How common is Down syndrome?.

Down syndrome is the most common chromosome-related condition in the U.S. Roughly 6,000 babies are born with the condition in the U.S. every year (about 1 in every 700 babies). More than 400,000 people are living with the condition in the U.S. today..