Chromosome Syndromes BY: Brandon and Kellen

Introduction The odds of having a child with a chromosome disorder/syndrome is 1 in 160 live births. (.00625%) Approximately half of these births will end up being a miscarriage. Trisomy is a condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities. (3 of the same chromosome.) Trisomy 21, better known as down syndrome, and is the most common chromosome syndrome in newborns. Trisomy 16 will always end up being a miscarriage.

Chromosome Syndrome A normal human will have 46 chromosomes, but people with chromosome disorders do not. That is why they may have a different appearance or act differently. People with these disorders have an altered amount of chromosome numbers. Due to these genetic diseases many of the results will end up in miscarriages or babies being born with mental retardation.

Chromosome syndrome Genetic disorders usually happen when abnormal genes are inherited from the parents. This is cases like monosomy or trisomy. Both of these are genetic abnormalities that result in mental retardation or are not compatible with life.

Diagnosis Children with a chromosome syndrome are usually diagnosed with a particular syndrome at birth. Doctors can visually see a disorder by the babies appearance. A further look into their chromosome will show what is particularly wrong with the baby.

Causes An extra or not enough chromosomes is the cause of mental disabilities. Women who are 35 and alder, who give birth to newborns have a 2% chance of a baby having a chromosome disorder.

Monosomy An alteration that can take place on a chromosome is in the form of monosomy. Monosomy is where there is only one chromosome, when there should be two. For example, Monosomy 21 is a rare chromosomal disorder where there is only one copy of chromosome 21 instead of the normal two. Monosomy cases are not compatible with life, and result in miscarriages and stillbirths.

Trisomy 21 Although many of these disorders results in death, one of them has a life expectancy that last over 55 years. That is down syndrome. Since the life expactancy is very long this can be considered the best chromosomal disorder. As you can see, the life expectancy has gone up by 31 years since the 80’s.

Trisomy 21general info. Trisomy 21 is what we call down syndrome. It is an extra copy of chromosome 21. The possibility of having a child with down syndrome is 1 in 800 live births. It was discovered in England by Dr. John Down in 1866.

Dr. John Down He was an English physician who devoted all his time to children with mental retardation. He noticed many similarities in all the children with down syndrome, which made him want to pursue a research project on it. He was unable to find the cause of it, but he is credited to discovering down syndrome, which led scientists to name it after him.

Trisomy 21 This condition leads to both the physical and the mental growth of the people who are born with it. Trisomy 21 is caused by an error in cell division called nondisjunction, which leaves a sperm or egg cell with an extra copy of chromosome 21 before or at conception. Nondisjunction- is the failure of chromosome pairs to separate properly during meiosis stage 1 or stage 2, specifically in the anaphase

Trisomy 21 On the left is what a normal person would look like and on the right is what a person with down syndrome would look like.

Other Chromosome Syndromes Trisomy 18, is also known as Edwards Syndrome. Trisomy 13, is also known as Patau Syndrome. Monosomy X, is also known as Turner-Ulrich Syndrome. XXY Syndrome, is also known as Klinefelter Syndrome. Most of these are chromosome disorders that may result in a miscarriage or mental retardation.