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Tuesday, March 19, 2013

Days 16, 17, 18, 19 and a Bonus for Trisomy 18

Day 16 - Ring Chromosomes

On our 16th day of MARCHING into TRISOMY AWARENESS MONTH, we are going to share about RING CHROMOSOMES. A ring chromosome is a chromosome in which both ends have been lost (deletion) and the two broken ends have reunited to form a ring-shaped figure. Ring chromosomes may form in cells following genetic damage by mutagens like radiation, but they may also arise spontaneously during development. The issue is that genetic information is often moved or deleted when a ring chromosome forms, and as a result, the genes on that chromosome may not express properly. This can lead to health problems which range from congenital conditions to cancer. Ring chromosomes are very rare, and they have been found in nearly all human chromosomes. Some people have ring chromosomes in their bodies and remain unaware of it, while in other cases, a suspected ring chromosome may be identified shortly after birth. The diversity of the spectrum from profound developmental delays to a blissfully unaware existence illustrates the diversity of human genetics. Share because you Care. ♥

Day 17 - Karotypes and Microarrays

On our 17th day of MARCHING into TRISOMY AWARENESS MONTH, we first want to wish our supporters a HAPPY ST. PATRICK'S DAY! Hope for Trisomy would love for you to share a photo of your blessing in GREEN! We are also going to share a genetic analogy. The process can be a little confusing, so we are hoping this analogy will help. Our chromosomes are like a set of 46 encyclopedia books. A chromosome analysis or karyotype is able to determine if there are any missing or extra books (chromosomes). Our genes are like the sentences on each page of the set of encyclopedia books (chromosomes), and each page of each book contains a unique set of sentences (genes). Each page contains the sentences for approximately 10 to 30 genes. A DNA microarray analysis is able to open up each of the 46 encyclopedia books to determine if there are any missing or extra pages. Our DNA are like the letters that make up each sentence (gene) on each page of the books (chromosomes). Each sentence is made up of a very specific sequence of letters (DNA). Genetic sequencing is able read a specific sentence to determine if there are any spelling mistakes (genetic mutations) in the sentence (gene). Share because you Care. ♥

Day 18 - Trisomy 18

On our 18th day of MARCHING into TRISOMY AWARENESS MONTH, we are going to share about the 2nd most common Trisomy behind Trisomy 21 (Down syndrome). Trisomy 18 (also called Edwards syndrome) is a genetic disorder where there are 3 copies of the 18th chromosome instead of the normal 2, and because of the third affects the child both physically and mentally. Unfortunately, there is a high mortality rate amongst the babies born with this disorder because of how that extra copy affects the development of the body. However, each child is affected differently and there is a wide spectrum of severity amongst babies born with this disorder. Here is a link provided by the SOFT Organization about TRISOMY 18 FACTS. Also, for the families caring for a child diagnosed with Trisomy 18, the SOFT Organization has a book provided at this link,
and a guidebook provided at this link. Share because you Care. ♥

Bonus T18 Share for the official Trisomy 18 Awareness Day!

One of the most notable things about trisomy 18 children are long and gorgeous eyelashes! Although eye problems are not one of the top concerns in a child with trisomy 18, we thought we'd share a photo example of their gorgeous eyes and share a list of some common Eye Features of Trisomy 18.

LONG EYELASHES - Although we can't find an actual publication that states this as a characteristic of trisomy 18, every T18 parent knows this! In fact, we like to joke that "the length of your eyelashes is directly proportional to the amount of 18th chromosomes you have." :-) That isn't really true, but there is definitely a correlation between long lashes and trisomy 18! All you have to do is look at just about any portrait of a T18 child.

WHORLED/ARCHED EYEBROWS - Commonly develop into a uni-brow too.

COLOBOMA - A small keyhold in the iris or other area of the eye.

PHOTOPHOBIA - Extreme light sensitivity causing sneezing, closing of eyes, aversion to light, etc.

Other eye anomalies can include blue sclerae, ptosis, microphthalmia, cataract, corneal opacities, strabismus.

If you look closely at this lovely T18 model's eyes, you can see somewhat tilted heart-shaped iris colobomas. ♥

Visit for facts, fun, advocacy, hope, and more!

Please note - 
Unless your child has other health issues, developmental delays, and other symptoms of a genetic disorder, you should not have to worry if they have some of these eye conditions. All of these eye conditions can occur in genetically normal persons. However, the whorled eyebrows and long lashes are one common feature of trisomy 18 children that parents readily recognize. They do occur in some other genetic disorders as well. So we thought it would be interesting to point out some common eye features for those with trisomy 18 children that may not have realized are "normal" for trisomy 18.  So please do not worry if your child has long eyelashes and bushy eyebrows, it is most likely just hereditary! But for those already diagnosed with a genetic condition, it may simply be a "normal" trait of that condition.

Day 19 - Translocations

On our 19th day of MARCHING into TRISOMY AWARENESS MONTH, we are going to share a little more about TRANSLOCATION, which is a structural abnormality in reference to chromosomes. Translocation is used when the location of specific chromosome material changes. The two main types of translocations are reciprocal and Robertsonian. In a reciprocal translocation, two different chromosomes have exchanged segments with each other. In a Robertsonian translocation, an entire chromosome attaches to another at the centromere. Translocations can be balanced or unbalanced. The balanced translocation is a rearrangement of the genetic material without any gain or loss of DNA. An unbalanced translocation IS a gain or loss of DNA, so the cell has an abnormal amount of genetic material. Often times, unbalanced translocations result in a birth defect, stillbirth, or a spontaneous abortion. Share because you Care. ♥

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