Sickle cell

Zahida Umar30-Nov-11

An inherited condition that results in a decrease in the ability of red blood cells to carry oxygen throughout the body

Sickle red blood cells become hard and irregularly

shaped (resembling a sickle)

Become clogged in the small blood vessels and

therefore do not deliver oxygen to the tissues.

Lack of tissue oxygenation can cause pain,

damage to body organs and even death.

Figure A shows normal red blood cells flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.

Figure B shows abnormal, sickled red blood cells clumping and blocking the blood flow in a blood vessel. The inset image shows a cross-section of a sickled red blood cell with abnormal strands of hemoglobin.

Source from http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_WhatIs.html

Mechanism

Red blood cells (RBC)

Contain a special protein called haemoglobin (Hb) Hb is the component that carries oxygen from the lungs

to all parts of the body

Most people have only hemoglobin type – Hb A within

RBC (normal genotype: Hb AA)

Sickle Cell: HbS

S similar to A, but one structural change

Mechanism -HbS

When sickle haemoglobin (HbS) gives up its oxygen to the tissues, HbS sticks together Forms long rods form inside RBC RBC become rigid, inflexible, and sickle-shaped Unable to squeeze through small blood vessels, instead

blocks small blood vessels Less oxygen to tissues of body

RBCs containing HbS have a shorter lifespan Normally 120 days Chronic state of anaemia

Figure A shows normal red blood cells flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.

Figure B shows abnormal, sickled red blood cells clumping and blocking the blood flow in a blood vessel. The inset image shows a cross-section of a sickled red blood cell with abnormal strands of hemoglobin.

Source from http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_WhatIs.html

Genetics 2 copies of the gene for

Hb (each parent)

HbS –Recessive S=Sickle A=Normal

Sickle Cell Trait

Sickle haemoglobin (S) + Normal haemoglobin (A) in RBC Adequate amount of normal Hb (A) in red blood cells

RBC remain flexible Carrier Do Not have the symptoms of the sickle cell disorders,

with 2 exceptions

1. Pain when Less Oxygen than usual (scuba diving, activities at high altitude (12,000ft), under general anaesthesia)

2. Minute kidney problems

Prevalence

More than 2.5 million Americans have the trait

70,000 or more Americans have sickle cell disease

About 1,000 babies are born with the disease each year in America In Nigeria, 1/3 population of U.S., 45,000-90,000

babies with sickle cell disease are born each year

Medical Complications

1. pain episodes

2. strokes

3. increased infections

4. leg ulcers

5. bone damage

6. yellow eyes or jaundice

7. lung blockage

8. kidney damage and loss of body water in urine

9. painful erections in men (priapism)

10.blood blockage in the spleen

11.eye damage

12.low red blood cell counts (anemia)

The Ultimate Cure? Gene Therapy

1. Correcting the “defective gene” and inserting it into the bone marrow

2. Turning off the defective gene and simultaneously reactivating another gene that turns on production of fetal hemoglobin.

No real cure for Sickle Cell Anemia at this time.

“In the past 30 years, the life expectancy of people with sickle cell anemia has increased. Many patients with sickle cell anemia now live into their mid-forties and beyond.”

Thank You

Websiteshttp://www.sicklecellsociety.org/ : Another Great Siteinformation, Counselling and Caring for those with Sickle Cell Disorders and their families: UK based

http://www.sicklecelldisease.org/: Sickle Cell Disease Association of America

The Human Genome Project Sickle Cell Education Site at http://www.massinteraction.org/html/genome/

http://www.ascaa.org/ American Sickle Cell Anemia AssociationASCAA was founded in 1971 and is the oldest sickle cell research, education, and social services organization in the United States.

http://www.ncd.gov/

http://www.painfoundation.org/

Sites for Kids

http://www.sicklecellsociety.org/sicklescene/pshomf.htm Planet Sickle Cell Society (UK based)-Youth support, Poetry, Pen-Pals, Information, Message

Board

http://www.starbright.org/The STARBRIGHT Foundation is dedicated to the development of projects that empower seriousl ill children to combat the medical and emotional challenges they face on a daily basis.

Coloring Books on Sickle Cell from Emory:http://www.emory.edu/PEDS/SICKLE/bbc/index.htmhttp://www.emory.edu/PEDS/SICKLE/chelate/index.htm