1. Find one normal karyotype on the male sex, and one normal Karyotype on the female sex, and then find 4 atypical karyotypes.
Answer:
1. NORMAL KARYOTYPE:
-Female Karyotype:contain two X chromosomes and are denoted 46,XX; males have both an X and a Y chromosome denoted 46,XY. Any variation from the standard karyotype may lead to developmental abnormalities.
-Female Karyotype:contain two X chromosomes and are denoted 46,XX; males have both an X and a Y chromosome denoted 46,XY. Any variation from the standard karyotype may lead to developmental abnormalities.
-Male Karyotype: Contain one X chromosome and one Y chromosome.
ATYPICAL KARYOTYPES:
-Turner Syndrome: Turner syndrome (TS) is a medical disorder that affects about 1 in every 2,500 girls. Although researchers don't know exactly what causes Turner syndrome, they do know that it's the result of a problem with a girl's chromosomes (pronounced: krow-muh-soamz).
Most girls are born with two X chromosomes, but girls with Turner syndrome are born with only one X chromosome or they are missing part of one X chromosome. The effects of the condition vary widely among girls with Turner syndrome. It all depends on how many of the body's cells are affected by the changes to the X chromosome.
Girls with Turner syndrome are usually short in height. Girls with Turner syndrome who aren't treated for short stature reach an average height of about 4 feet 7 inches (1.4 meters). The good news is that when Turner syndrome is diagnosed while a girl is still growing, she can be treated with growth hormones to help her grow taller.
In addition to growth problems, Turner syndrome prevents the ovaries from developing properly, which affects a girl's sexual development and the ability to have children. Because the ovaries are responsible for making the hormones that control breast growth and menstruation, most girls with Turner syndrome will not go through all of the changes associated with puberty unless they get treatment for the condition. Nearly all girls with Turner syndrome will be infertile, or unable to become pregnant on their own.
-Medical problems
Children with Down syndrome are at higher risk to develop a number of specific medical problems. While most people with Down syndrome do not have serious medical problems, it is good to be aware of potential complications so that appropriate medical treatment can be sought early before serious complications arise.
Almost all infants with Down syndrome have low muscle tone which is called hypotonia. This means that their muscles are somewhat weak and they appear floppy. While this isn’t a medical problem per se, it is important because muscle tone can affect a child with Down syndrome’s ability to learn and grow. Hypotonia cannot be cured but it generally improves over time.
Hypotonia can also lead to some of the orthopedic or bone problems such at atlantoaxial instability that some people with Down syndrome can have.
The majority of children with Down syndrome will have some type of vision problem such as nearsightedness, farsightedness, crossed-eyes and even blocked tear ducts. About 40% of babies with Down syndrome are born with heart defects which can range from mild to severe. Somewhere between 40-60% of babies with Down syndrome will have some form of hearing loss. Other problems seen less frequently include gastrointestinal defects, thyroid problems and very rarely leukemia.
-Mental Retardation
All individuals with Down syndrome have some degree of mental retardation. They learn more slowly and have difficulties with complex reasoning and judgement, but they do have the capacity to learn. It is impossible to predict the degree of mental retardation in an infant with Down syndrome at birth (just as it is impossible to predict the IQ of any infant at birth).
It is very important that infant and people with Down syndrome receive the support, guidance, education and appropriate treatments needed to maximize their potential and to allow them to live fulfilling lives.
· Trisomy 18: There are 23 pairs of human chromosomes. In Trisomy 18 (Edwards syndrome), there is an extra chromosome with the 18th pair.
Trisomy 18 occurs in 1 in 3,000 live births. Unfortunately, most babies with Trisomy 18 die before birth, so the actual incidence of the disorder may be higher. Trisomy 18 affects individuals of all ethnic backgrounds.
-Trisomy 18 severely affects all organ systems of the body. Symptoms may include:
· Nervous system and brain - mental retardation and delayed development, high muscle tone,seizures, and physical malformations such as brain defects
· Head and face - small head (microcephaly), small eyes, wide-set eyes, small lower jaw
· Heart - congenital heart defects such as ventricular septal defect
· Bones - severe growth retardation, clenched hands with 2nd and 5th fingers on top of the others, and other defects of the hands and feet
· Malformations of the digestive tract, the urinary tract, and genitals
-Diagnosis
The physical appearance of the child at birth will suggest the diagnosis of Trisomy 18. However, most babies are diagnosed before birth by amniocentesis (genetic testing of the amniotic fluid). Ultrasounds of the heart and abdomen can detect abnormalities, as can x-rays of the skeleton.
· X X X syndrome: XXX syndrome (also called Trisomy X or Triple X) is caused by the presence of an extra ‘X’ chromosome in every cell. Typically, a female has two X chromosomes in every cell of their body, so the extra ‘X’ is unusual. The extra ‘X’ chromosome is typically inherited from the mother, but is a random event—not caused by anything she did or could prevent. Trisomy X is often not diagnosed until later in life, if ever. The risk of having a second child with an extra chromosome is approximately 1%, until mom is older than 38 years of age, as it is thought that this random event becomes more common as a woman ages. Prenatal testing is available in future pregnancies.
-Treatment: XXX syndrome is diagnosed prenatally, through CVS or amniocentesis, or after the child is born by a blood test. These tests are all able to look at a person’s chromosomes (karyotype.) There is no way to remove the extra X chromosome. Treatment depends on what needs the child has. Girls with XXX syndrome may need to be seen by physical, developmental, occupational, or speech therapists if they have developmental or speech problems. Additionally, a pediatric psychologist or group therapy may be helpful if they have social troubles. Girls with Trisomy X are treated as any other child with a developmental or psychological concern would be treated.
· Klinefelter syndrome: also known as the XXY condition, is a term used to describe males who have an extra X chromosome in most of their cells. Instead of having the usual XY chromosome pattern that most males have, these men have an XXY pattern.
Klinefelter syndrome is named after Dr. Henry Klinefelter, who first described a group of symptoms found in some men with the extra X chromosome. Even though all men with Klinefelter syndrome have the extra X chromosome, not every XXY male has all of those symptoms.
Because not every male with an XXY pattern has all the symptoms of Klinefelter syndrome, it is common to use the term XXY male to describe these men, or XXY condition to describe the symptoms.
Scientists believe the XXY condition is one of the most common chromosome abnormalities in humans. About one of every 500 males has an extra X chromosome, but many don’t have any symptoms.
For more information on genes and chromosomes.
-Symptoms
Not all males with the condition have the same symptoms or to the same degree. Symptoms depend on how many XXY cells a man has, how much testosterone is in his body, and his age when the condition is diagnosed.
The XXY condition can affect three main areas of development:
Physical development: As babies, many XXY males have weak muscles and reduced strength. They may sit up, crawl, and walk later than other infants. After about age four, XXY males tend to be taller and may have less muscle control and coordination than other boys their age.
As XXY males enter puberty, they often don’t make as much testosterone as other boys. This can lead to a taller, less muscular body, less facial and body hair, and broader hips than other boys. As teens, XXY males may have larger breasts, weaker bones, and a lower energy level than other boys.
By adulthood, XXY males look similar to males without the condition, although they are often taller. They are also more likely than other men to have certain health problems, such as autoimmune disorders, breast cancer, vein diseases, osteoporosis, and tooth decay.
XXY males can have normal sex lives, but they usually make little or no sperm. Between 95 percent and 99 percent of XXY males are infertile because their bodies don’t make a lot of sperm.
· Patau syndrome: Trisomy 13, is the least common of the autosomal trisomies, after Down syndrome (Trisomy 21) and Edwards syndrome (Trisomy 18). The extra copy of chromosome 13 in Patau syndrome causes severe neurological and heart defects which make it difficult for infants to survive. The exact incidence of Patau syndrome is not known, although it appears to affect females more than males, most likely because male fetuses do not survive until birth. Patau syndrome, like Down syndrome, is associated with increased age of the mother. It may affect individuals of all ethnic backgrounds.
-Symptoms
Newborns with Patau syndrome share common physical characteristics:
· Extra fingers or toes (polydactyly)
· Deformed feet, known as rocker-bottom feet
· Neurological problems such as small head (microcephaly), failure of the brain to divide into halves during gestation (holoprosencephaly), severe mental deficiency
· Facial defects such as small eyes (microphthalmia), absent or malformed nose, cleft lip and/or cleft palate
· Heart defects (80% of individuals)
· Kidney defects
-Treatment
Treatment of Patau syndrome focuses on the particular physical problems with which each child is born. Many infants have difficulty surviving the first few days or weeks due to severe neurological problems or complex heart defects. Surgery may be necessary to repair heart defects or cleft lip and cleft palate. Physical, occupational, and speech therapy will help individuals with Patau syndrome reach their full developmental potential.
-Medical problems
Children with Down syndrome are at higher risk to develop a number of specific medical problems. While most people with Down syndrome do not have serious medical problems, it is good to be aware of potential complications so that appropriate medical treatment can be sought early before serious complications arise.
Hypotonia can also lead to some of the orthopedic or bone problems such at atlantoaxial instability that some people with Down syndrome can have.
The majority of children with Down syndrome will have some type of vision problem such as nearsightedness, farsightedness, crossed-eyes and even blocked tear ducts. About 40% of babies with Down syndrome are born with heart defects which can range from mild to severe. Somewhere between 40-60% of babies with Down syndrome will have some form of hearing loss. Other problems seen less frequently include gastrointestinal defects, thyroid problems and very rarely leukemia.
-Mental Retardation
All individuals with Down syndrome have some degree of mental retardation. They learn more slowly and have difficulties with complex reasoning and judgement, but they do have the capacity to learn. It is impossible to predict the degree of mental retardation in an infant with Down syndrome at birth (just as it is impossible to predict the IQ of any infant at birth).
It is very important that infant and people with Down syndrome receive the support, guidance, education and appropriate treatments needed to maximize their potential and to allow them to live fulfilling lives.
· Trisomy 18: There are 23 pairs of human chromosomes. In Trisomy 18 (Edwards syndrome), there is an extra chromosome with the 18th pair.
-Trisomy 18 severely affects all organ systems of the body. Symptoms may include:
· Nervous system and brain - mental retardation and delayed development, high muscle tone,seizures, and physical malformations such as brain defects
· Head and face - small head (microcephaly), small eyes, wide-set eyes, small lower jaw
· Heart - congenital heart defects such as ventricular septal defect
· Bones - severe growth retardation, clenched hands with 2nd and 5th fingers on top of the others, and other defects of the hands and feet
· Malformations of the digestive tract, the urinary tract, and genitals
-Diagnosis
The physical appearance of the child at birth will suggest the diagnosis of Trisomy 18. However, most babies are diagnosed before birth by amniocentesis (genetic testing of the amniotic fluid). Ultrasounds of the heart and abdomen can detect abnormalities, as can x-rays of the skeleton.
· X X X syndrome: XXX syndrome (also called Trisomy X or Triple X) is caused by the presence of an extra ‘X’ chromosome in every cell. Typically, a female has two X chromosomes in every cell of their body, so the extra ‘X’ is unusual. The extra ‘X’ chromosome is typically inherited from the mother, but is a random event—not caused by anything she did or could prevent. Trisomy X is often not diagnosed until later in life, if ever. The risk of having a second child with an extra chromosome is approximately 1%, until mom is older than 38 years of age, as it is thought that this random event becomes more common as a woman ages. Prenatal testing is available in future pregnancies.
· Klinefelter syndrome: also known as the XXY condition, is a term used to describe males who have an extra X chromosome in most of their cells. Instead of having the usual XY chromosome pattern that most males have, these men have an XXY pattern.
Klinefelter syndrome is named after Dr. Henry Klinefelter, who first described a group of symptoms found in some men with the extra X chromosome. Even though all men with Klinefelter syndrome have the extra X chromosome, not every XXY male has all of those symptoms.
Because not every male with an XXY pattern has all the symptoms of Klinefelter syndrome, it is common to use the term XXY male to describe these men, or XXY condition to describe the symptoms.
Scientists believe the XXY condition is one of the most common chromosome abnormalities in humans. About one of every 500 males has an extra X chromosome, but many don’t have any symptoms.
For more information on genes and chromosomes.
-Symptoms
Not all males with the condition have the same symptoms or to the same degree. Symptoms depend on how many XXY cells a man has, how much testosterone is in his body, and his age when the condition is diagnosed.
The XXY condition can affect three main areas of development:
Physical development: As babies, many XXY males have weak muscles and reduced strength. They may sit up, crawl, and walk later than other infants. After about age four, XXY males tend to be taller and may have less muscle control and coordination than other boys their age.
As XXY males enter puberty, they often don’t make as much testosterone as other boys. This can lead to a taller, less muscular body, less facial and body hair, and broader hips than other boys. As teens, XXY males may have larger breasts, weaker bones, and a lower energy level than other boys.
By adulthood, XXY males look similar to males without the condition, although they are often taller. They are also more likely than other men to have certain health problems, such as autoimmune disorders, breast cancer, vein diseases, osteoporosis, and tooth decay.
XXY males can have normal sex lives, but they usually make little or no sperm. Between 95 percent and 99 percent of XXY males are infertile because their bodies don’t make a lot of sperm.
· Patau syndrome: Trisomy 13, is the least common of the autosomal trisomies, after Down syndrome (Trisomy 21) and Edwards syndrome (Trisomy 18). The extra copy of chromosome 13 in Patau syndrome causes severe neurological and heart defects which make it difficult for infants to survive. The exact incidence of Patau syndrome is not known, although it appears to affect females more than males, most likely because male fetuses do not survive until birth. Patau syndrome, like Down syndrome, is associated with increased age of the mother. It may affect individuals of all ethnic backgrounds.
-Symptoms
Newborns with Patau syndrome share common physical characteristics:
· Extra fingers or toes (polydactyly)
· Deformed feet, known as rocker-bottom feet
· Neurological problems such as small head (microcephaly), failure of the brain to divide into halves during gestation (holoprosencephaly), severe mental deficiency
· Facial defects such as small eyes (microphthalmia), absent or malformed nose, cleft lip and/or cleft palate
· Heart defects (80% of individuals)
· Kidney defects
-Treatment
Treatment of Patau syndrome focuses on the particular physical problems with which each child is born. Many infants have difficulty surviving the first few days or weeks due to severe neurological problems or complex heart defects. Surgery may be necessary to repair heart defects or cleft lip and cleft palate. Physical, occupational, and speech therapy will help individuals with Patau syndrome reach their full developmental potential.
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