Sickle cell anaemia | Genetics | Biology | FuseSchool

Summary

Sickle cell anemia is an inherited disorder affecting red blood cells due to a mutation in the hemoglobin gene, causing them to become crescent-shaped and prone to blockages. This can lead to severe pain crises and life-threatening complications. The condition is inherited recessively, requiring two faulty alleles, and is prevalent in regions where malaria is common due to its protective effect against the disease. Carriers have a 50% abnormal hemoglobin, which hinders the malaria parasite's life cycle, thus reducing its prevalence.

Takeaways

• 🧬 Sickle cell anemia is an inherited disorder affecting red blood cells due to a mutation in the hemoglobin gene.
• 🩸 Normal red blood cells are round and flexible, but in sickle cell anemia, they become crescent or 'sickle' shaped due to the faulty hemoglobin.
• 🚫 The misshapen red blood cells can cause blockages in blood vessels, preventing oxygen and glucose from reaching tissues and organs.
• 😖 Sickle cell crises are episodes of severe pain that can last from minutes to weeks and may lead to life-threatening complications.
• 🧬 To have sickle cell anemia, an individual must inherit two copies of the recessive allele, while one copy makes a person a carrier.
• 👨‍👩‍👧‍👦 Carriers have red blood cells with 50% abnormal hemoglobin, making them more fragile but not causing the disease.
• 🌍 The distribution of sickle cell anemia is linked to regions where malaria is prevalent, particularly in central Africa, India, the Middle East, and among people of African descent.
• 🦟 The sickle cell allele offers a protective effect against malaria, as the parasite's life cycle is disrupted in the fragile red blood cells of carriers.
• 📈 The prevalence of sickle cell anemia is higher in malaria regions because carriers have a higher chance of passing on the allele to their children.
• 🌐 There are approximately 4.4 million people worldwide with sickle cell anemia and an additional 43 million carriers.
• 👍 The video encourages viewers to like, subscribe, and comment if they have questions, and also to check out the Few School app for more information.

Q & A

What is sickle cell anemia?

Sickle cell anemia is an inherited disorder that affects red blood cells due to a mutation in the hemoglobin gene, causing them to assume a crescent or 'sickle' shape, which can lead to blockages in blood vessels and a lack of oxygen to tissues and organs.

What role does hemoglobin play in the body?

Hemoglobin is a red protein in red blood cells that carries oxygen throughout the body.

How do red blood cells normally function and what changes in sickle cell anemia?

Normally, red blood cells are round and flexible, allowing them to move easily through narrow blood vessels. In sickle cell anemia, the mutation causes the cells to become inflexible and sickle-shaped, which can obstruct blood flow.

What is a sickle cell crisis?

A sickle cell crisis is a painful episode caused by blockages in blood vessels due to the sickle-shaped red blood cells, preventing oxygen and glucose from reaching cells, and can last from minutes to weeks.

How can sickle cell anemia be inherited?

Sickle cell anemia is inherited when an individual has two copies of the faulty, recessive allele. People with one copy are carriers and have a mix of normal and abnormal hemoglobin.

What is the significance of a Punnett square in understanding inheritance of sickle cell anemia?

A Punnett square can be used to predict the possible genotypes of offspring when both parents are carriers of the sickle cell trait, showing the chances of having children with the disorder, as carriers, or unaffected.

How many people are affected by sickle cell anemia worldwide?

Approximately 4.4 million people worldwide have sickle cell anemia, and an additional 43 million are carriers.

Why is sickle cell anemia more common in certain regions of the world?

Sickle cell anemia is more common in regions such as Central Africa, parts of India, the Middle East, and among people of African origin in other parts of the world, which also have a high prevalence of malaria.

How does the sickle cell allele provide protection against malaria?

The sickle cell allele offers protection against malaria by causing the red blood cells of carriers to be more fragile, often bursting when invaded by the malaria parasite, thus killing the parasite and interrupting its life cycle.

What is the relationship between the prevalence of sickle cell anemia and malaria?

The prevalence of sickle cell anemia is higher in regions affected by malaria because the sickle cell allele, while causing the disorder, also provides a survival advantage against malaria, leading to a higher likelihood of the allele being passed on.

How can individuals learn more about sickle cell anemia and related topics?

Individuals can learn more about sickle cell anemia and related topics through educational videos, subscribing to relevant channels, using educational apps like Few School, and asking questions in the comment sections of these platforms.

Outlines

00:00

🩸 Understanding Sickle Cell Anemia

This paragraph delves into sickle cell anemia, an inherited disorder that impacts the red blood cells' shape and function due to a mutation in the hemoglobin gene. It explains how normal red blood cells are round and flexible, allowing them to easily navigate the body's blood vessels. However, in sickle cell anemia, the mutated hemoglobin causes red blood cells to become crescent-shaped and inflexible, leading to potential blockages in blood vessels. These blockages can result in a painful condition known as a sickle cell crisis, which may last from minutes to weeks and can be life-threatening if it affects vital organs like the brain. The paragraph also covers the genetic inheritance of the disorder, noting that having two copies of the faulty allele is necessary for the disease to manifest, while one copy makes a person a carrier with slightly more fragile red blood cells.

Keywords

💡Sickle Cell Anemia

Sickle Cell Anemia is a genetic disorder that affects the shape and function of red blood cells. It is the main theme of the video as it explains how this condition is inherited and its impact on the body. In the script, it is described as a disorder where red blood cells become crescent or 'sickle' shaped due to a mutation in the hemoglobin gene, leading to various health complications.

💡Inherited Disorder

An inherited disorder is a health condition that is passed down through families in their DNA. In the context of the video, sickle cell anemia is an inherited disorder because it can be passed from parents to their children through the genes. The script explains that having two copies of the faulty allele is necessary to have the disorder.

💡Hemoglobin

Hemoglobin is a red protein in red blood cells that carries oxygen throughout the body. The video script describes how a mutation in the hemoglobin gene in individuals with sickle cell anemia causes the red blood cells to form strands, making them inflexible and sickle-shaped.

💡Red Blood Cells

Red blood cells are the most common type of blood cell and are responsible for transporting oxygen from the lungs to the body's tissues. The video emphasizes that in sickle cell anemia, these cells are affected, becoming inflexible and sickle-shaped, which can obstruct blood flow and cause health crises.

💡Crescent Shape

The term 'crescent shape' describes the abnormal shape of red blood cells in individuals with sickle cell anemia. The script mentions this shape as a result of the faulty hemoglobin, which makes the cells rigid and leads to their characteristic sickle or crescent shape.

💡Blockages

Blockages refer to the obstructions in blood vessels caused by the sickle-shaped red blood cells. The video script explains that these blockages can prevent cells and tissues from receiving oxygen and glucose, leading to a sickle cell crisis and causing severe pain.

💡Sickle Cell Crisis

A sickle cell crisis is a painful episode that occurs when the sickle-shaped red blood cells block blood flow to tissues and organs. The script describes the symptoms of a crisis, which can be severe and last from minutes to weeks, and can even lead to life-threatening complications such as strokes.

💡Allele

An allele is a variant form of a gene. The video script discusses the concept of having two copies of the faulty allele for sickle cell anemia to manifest. It also mentions that individuals with one copy are carriers, having some abnormal hemoglobin but not the full disorder.

💡Carriers

Carriers are individuals who have one copy of the recessive allele for a genetic disorder but do not exhibit the disorder themselves. In the script, it is explained that carriers of the sickle cell allele have red blood cells with 50% abnormal hemoglobin, making them slightly more fragile than normal.

💡Punnett Square

A Punnett square is a diagram used to predict the genotypes of offspring from a particular cross. The video script uses the Punnett square to illustrate the possible genetic outcomes when two carrier parents have children, including the potential for the child to have sickle cell anemia or be a carrier.

💡Malaria

Malaria is a disease caused by parasites that are transmitted by mosquitoes. The video script discusses the correlation between the prevalence of sickle cell anemia and malaria, explaining that the sickle cell allele provides some protection against malaria, which is why it is more common in regions where malaria is prevalent.

Highlights

Sickle cell anemia is an inherited disorder affecting red blood cells.

It is passed from parent to child due to its inherited nature.

Red blood cells with hemoglobin carry oxygen throughout the body.

Normal red blood cells are round and flexible for easy movement in blood vessels.

People with sickle cell anemia have a mutation in the hemoglobin gene.

Faulty hemoglobin causes red blood cells to become inflexible and sickle-shaped.

Sickle-shaped red blood cells can cause blockages in blood vessels.

Blockages prevent oxygen and glucose delivery, leading to sickle cell crisis.

Sickle cell crisis symptoms can be severe and last from minutes to weeks.

Complications from blockages can be life-threatening, such as strokes.

To have sickle cell anemia, one must inherit two copies of the faulty allele.

Carriers have one copy of the recessive allele and red blood cells with 50% abnormal hemoglobin.

Carriers' red blood cells are slightly more fragile than normal.

Children of two carrier parents can be affected, carriers, or unaffected.

About 4.4 million people worldwide have sickle cell anemia, with 43 million carriers.

Sickle cell anemia is more common in regions also affected by malaria.

The sickle cell allele provides protection against malaria by causing red blood cells to burst.

Regions with higher malaria rates have increased numbers of sickle cell anemia sufferers.

The video explains sickle cell anemia, its inheritance, and geographical prevalence.

Transcripts

[Music]

sickle cell anemia is an inherited

disorder that affects the red blood

cells

because it is inherited it means that it

can be passed from parent to child

so what is it

red blood cells contain red protein

called hemoglobin which carries oxygen

around the body

normally red blood cells are round and

flexible which means they can bend to

move easily through the narrow blood

vessels

people with sickle cell anemia have a

change or mutation in the hemoglobin

gene

this faulty version of the gene causes

the hemoglobin to form strands in the

red blood cells which makes them

inflexible and gives them a crescent or

a sickle shape this is where the name of

the disorder comes from a sickle is a

tool used to cut long grass these

unusually shaped red blood vessels can

cause blockages in sections of the blood

vessels

red blood cells cannot pass through the

blockages to reach the cells in tissues

and organs so the cells cannot get

oxygen and glucose for respiration when

this happens it causes pain called a

sickle cell crisis

the symptoms of a crisis can be severe

and last from a few minutes to several

weeks

it can cause complications which can be

life-threatening

for example if a blockage occurs in the

blood vessels in the brain then brain

cells can die which causes a stroke so

how is sickle cell anemia inherited

well to have the disorder you have to

have two copies of the faulty allele

which is a recessive allele people who

have one copy of the recessive allele

are carriers the red blood cells of

carriers have 50 abnormal hemoglobin and

are slightly more fragile than normal if

these two sickle cell carrier parents

have offspring they can have children

with the disorder children who are also

carriers or children who are completely

unaffected

which we can show in a punnett square

there are about 4.4 million people in

the world who have sickle cell anemia

while an additional 43 million are

carriers

about 80 percent of people with sickle

cell anemia live in central africa it

also occurs relatively frequently in

parts of india the middle east and among

people of african origin living in other

parts of the world

these regions are also most affected by

the disease malaria

this is not a coincidence having the

sickle cell allele actually protects you

against malaria this means you are more

likely to survive childhood and pass on

the sickle cell allele to your children

this also means that the numbers

suffering from sickle cell anemia are

also higher in malaria regions because

if two carriers have children they have

an increased risk of having children

with the disorder but how does carrying

the sickle cell allele help protect

against malaria the malarial parasite is

transmitted by female mosquitoes which

spend part of its life cycle inside red

blood cells when these parasites enter

the fragile red blood cells of carriers

the cells often burst before the

parasite has time to develop

this means the parasite dies and the

life cycle is broken

so in this video you have learnt what

sickle cell anemia is how it is

inherited and why it is more common in

some areas of the world than others

if you liked the video give it a thumbs

up and don't forget to subscribe comment

below if you have any questions why not

check out our few school app as well

until next time