Trisomy Awareness Month Catch Up Time! (Days 23-25) Insertion, Deletion, and Duplication

Illness hit our family - that wonderful stomach bug that lasts for days. And, unfortunately, I was the one having to take care of everyone! We survived just in time for our spring break week. But we went out of town and were without Internet or PC, so I couldn't continue the posts. So I am catching up! These excellent summaries are posted on our Hope for Trisomy Facebook page. Please become a fan!

Day 23: Insertion

On our 23rd day of MARCHING into TRISOMY AWARENESS MONTH, we are going to share a little more about the STRUCTURAL ABNORMALITY called an INSERTION. An insertion is when a portion of one chromosome has been deleted from its original place and inserted into another chromosome. Insertions can be anywhere in size from one base pair incorrectly inserted into a DNA sequence to a section of one chromosome inserted into another.The insertion changes the number of DNA bases in a gene by adding a piece of DNA. As a result, the protein made by the gene may not function properly. Insertions can be particularly hazardous if they occur in an exon, the amino acid coding region of a gene. It can possibly result in any number of genetic disorders depending on the gene in which the insertion occurs. Share because you Care. ♥

Day 24: Deletion

On our 24th day of MARCHING into TRISOMY AWARENESS MONTH, we are going to share a little more about the STRUCTURAL ABNORMALITY called DELETION. A deletion occurs when some genetic material is lost when a chromosome breaks. A deletion can occur on any chromosome, at any band, and can be any size (small, medium or large). How big a piece is missing and what genes are missing in the section will depend on what the deletion causes. Small deletions are less likely to be fatal. Medium-sized deletions can lead to disorders like Williams syndrome. Large deletions are usually fatal, and there are always variations based on which genes are lost. Deletions are responsible for an array of genetic disorders, including some cases of male infertility and two thirds of the cases of Duchenne muscular dystrophy. When there is a deletion in part of the short arm of chromosome 5, this results in Cri du chat syndrome. A chromosome deletion causes many different disorders. There are also many different symptoms and severity of symptoms depending on which chromosome was deleted and how much. Here is an example of a chromosome finding; 46,XX,del(14)(q23)
This means...a female with 46 chromosomes with a deletion of chromosome 14 on the long arm (q) at band 23. Share because you Care. ♥

Day 25: Duplication

On our 25th day of MARCHING into TRISOMY AWARENESS MONTH, we are going to share a little more about the STRUCTURAL ABNORMALITY called DUPLICATION. A chromosome duplication is the doubling of a chromosome piece. A duplication can have the production of one or more copies of any piece of DNA, including sometimes a gene or even an entire chromosome. A duplication is sometimes referred as a 'partial trisomy'. This means the individual has three copies of that area instead of two. Therefore, there are extra instructions (genes) present that can cause an increased risk for birth defects or developmental problems. Charcot-Marie-Tooth disease type I is a disease related to a chromosomal duplication. Here is an example of a chromosome finding; 46,XY,dup(7)(q11.2q22) This means...a male with a duplication of chromosome 7 on the long arm (q) between bands 11.2 to 22. Share because you Care. ♥