biology project

Sickle-Cell Disease
Discovery:
http://www.sicklecellanaemia.org/sickle-cell-disease/discovery-of-sickle-cell-disease
James Herrick was a doctor in Chicago, USA, and wrote about his observations of a patient with severe anaemia. When blood samples were viewed under the microscope Herrick noted “peculiar elongated and sickle-shaped red blood corpuscles”.

Symptoms: http://www.nhlbi.nih.gov/health/health-topics/topics/sca/ Sickle cell anemia varies from person to person. Some people who have the disease have chronic (long-term) pain or fatigue (tiredness).
Because of improved treatments and care, people who have sickle cell anemia are now living into their forties or fifties, or longer.
Sickle cells are stiff and sticky. They tend to block blood flow in the blood vessels of the limbs and organs. Blocked blood flow can cause pain and organ damage. It can also raise the risk for infection.

http://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/basics/symptoms/con-20019348
Signs and symptoms of sickle cell anemia usually show up after an infant is 4 months old and may include:
Anemia. Sickle cells are fragile. They break apart easily and die, leaving you chronically short on red blood cells. Red blood cells usually live for about 120 days before they die and need to be replaced. However, sickle cells die after only 10 to 20 days. The result is a chronic shortage of red blood cells, known as anemia. Without enough red blood cells in circulation, your body can't get the oxygen it needs to feel energized. That's why anemia causes fatigue.
Episodes of pain. Periodic episodes of pain, called crises, are a major symptom of sickle cell anemia. Pain develops when sickle-shaped red blood cells block blood flow through tiny blood vessels to your chest, abdomen and joints. Pain can also occur in your bones. The pain may vary in intensity and can last for a few hours to a few weeks. Some people experience only a few episodes of pain. Others experience a dozen or more crises a year. If a crisis is severe enough, you may need to be hospitalized.
Hand-foot syndrome. Swollen hands and feet may be the first signs of sickle cell anemia in babies. The swelling is caused by sickle-shaped red blood cells blocking blood flow out of their hands and feet.
Frequent infections. Sickle cells can damage your spleen, an organ that fights infection. This may make you more vulnerable to infections. Doctors commonly give infants and children with sickle cell anemia antibiotics to prevent potentially life-threatening infections, such as pneumonia.
Delayed growth. Red blood cells provide your body with the oxygen and nutrients you need for growth. A shortage of healthy red blood cells can slow growth in infants and children and delay puberty in teenagers.
Vision problems. Some people with sickle cell anemia experience vision problems. Tiny blood vessels that supply your eyes may become plugged with sickle cells. This can damage the retina — the portion of the eye that processes visual images.

Receiving the disorder: http://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/basics/causes/con-20019348 The sickle cell gene is passed from generation to generation in a pattern of inheritance called autosomal recessive inheritance. This means that both the mother and the father must pass on the defective form of the gene for a child to be affected.
If only one parent passes the sickle cell gene to the child, that child will have the sickle cell trait. With one normal hemoglobin gene and one defective form of the gene, people with the sickle cell trait make both normal hemoglobin and sickle cell hemoglobin. Their blood may contain some sickle cells, but they generally don't experience symptoms. However, they are carriers of the disease, which means they can pass the defective gene on to their children.

Karyotype: http://scisosbiol.wordpress.com/2011/03/02/the-karyotype-of-the-sickle-cell-disease/ Diagnosis: http://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/basics/tests-diagnosis/con-20019348 A blood test can check for hemoglobin S — the defective form of hemoglobin that underlies sickle cell anemia. In the United States, this blood test is part of routine newborn screening done at the hospital. But older children and adults can be tested, too.
If the screening test is negative, there is no sickle cell gene present. If the screening test is positive, further tests will be done to determine whether one or two sickle cell genes are present. People who have one gene — sickle cell trait — have a fairly small percentage of hemoglobin S. People with two genes — sickle cell disease — have a much larger percentage of the defective hemoglobin.

Treatment: http://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/basics/treatment/con-20019348 Bone marrow transplant offers the only potential cure for sickle cell anemia. But, finding a donor is difficult and the procedure has serious risks associated with it, including death.
As a result, treatment for sickle cell anemia is usually aimed at avoiding crises, relieving symptoms and preventing complications. If you have sickle cell anemia, you'll need to make regular visits to your doctor to check your red blood cell count and monitor your health. Treatments may include medications to reduce pain and prevent complications, blood transfusions and supplemental oxygen, as well as bone marrow transplant.

http://www.nlm.nih.gov/medlineplus/magazine/issues/winter11/articles/winter11pg21.html
In 2010, a study found that neurologically normal adults with sickle cell disease scored lower on tests of brain function than neurologically normal adult participants who did not have sickle cell disease

http://www.sharecare.com/health/chromosomal-disorders/research-done-cri-du-chat
They believe that one gene, called CTNND2, is responsible for the loss of intellectual ability. http://ndsccenter.org/resources/general-information/ds-news-articles/current-research-in-down-syndrome/ There is ongoing research to identify the structure and the function of these proteins and how they affect the phenotype.

SS-homozygous normal
Ss-heterozygous Sickle Cell trait ss-homozygous sickle cell disease

S s S SS Ss

s Ss ss

Cri du chat
Discovery:
http://www.criduchat.asn.au/content/cri-du-chat-syndrome syndrome was originally named in 1963 by geneticist Jerome Lejeune, is the distinctive high-pitched, monotone, cat-like cry. "Cri du Chat" is French for "cat's cry".
Symptoms:
https://www.genome.gov/19517558
The variability of the clinical symptoms and developmental delays may be related to the size of the deletion of the 5p arm. high-pitched cat-like cry, mental retardation, delayed development, distinctive facial features, small head size (microcephaly), widely-spaced eyes (hypertelorism), low birth weight and weak muscle tone (hypotonia) in infancy. most individuals with cri du chat syndrome have a normal life expectancy.

Receiving The Disorder: https://www.genome.gov/19517558 Most cases of cri du chat syndrome are not inherited. The chromosomal deletion usually occurs as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. People with cri du chat typically have no history of the condition in their family.

Treatment: https://www.genome.gov/19517558 No specific treatment is available for this syndrome. With early and consistent educational intervention, as well as physical and language therapy, children with cri du chat syndrome are capable of reaching their fullest potential and can lead full and meaningful lives.

Diagnosis:

https://www.genome.gov/19517558
The diagnosis of cri du chat syndrome is generally made in the hospital at birth. A health care provider may note the clinical symptoms associated with the condition. The cat-like cry is the most prominent clinical feature in newborn children and is usually diagnostic for the cri du chat syndrome.
Additionally, analysis of the individual's chromosomes may be performed. The missing portion (deletion) of the short arm of chromosome 5 may be seen on a chromosome analysis. If not, a more detailed type of genetic test called FISH analysis may be needed to reveal the deletion.

http://criduchat-science.blogspot.com/2007/02/karyotype-for-cri-du-chat.html

Down Syndrome(Trisomy 21)
Discovery:
http://www.downs-syndrome.org.uk/component/content/article/35-general/160-4-when-was-downs-syndrome-discovered.html
It is believed that people with Down's syndrome have always existed. However, it was not until 1866 that the English doctor, John Langdon Down published a description of the condition, which subsequently took his name.
In 1959 Professor Jérome Lejeune proved that Down's syndrome is a chromosomal irregularity. Instead of 46 chromosomes usually present in each cell, Lejeune noted 47 in the cells of people with Down's syndrome. It was later determined that this additional chromosomal material results in the physical characteristics associated with the condition and the different course in development.
Symptoms:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001992/
Decreased muscle tone at birth
Excess skin at the nape of the neck
Flattened nose
Separated joints between the bones of the skull (sutures)
Single crease in the palm of the hand
Small ears
Small mouth
Upward slanting eyes
Wide, short hands with short fingers
White spots on the colored part of the eye (Brushfield spots)
Impulsive behavior
Poor judgment
Short attention span
Slow learning
Treatment:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001992/
There is no specific treatment for Down syndrome.
Diagnosis:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001992/
A doctor can often make an initial diagnosis of Down syndrome at birth based on how the baby looks. The doctor may hear a heart murmur when listening to the baby's chest with a stethoscope.
A blood test can be done to check for the extra chromosome and confirm the diagnosis.