Jada Bascom Foundation
Donate Now

Inherited red blood cell disorders

Sickle cell disease

If you or someone you love has just heard this diagnosis, start here. This guide explains what the condition is, how it is usually treated and where a transplant fits.

Sickle cell disease is a group of inherited hemoglobin disorders that can cause anemia, pain, infection and organ injury. Medicines, prevention and transfusion are central to care. A donor transplant or gene therapy can offer a major change in disease course for selected people, with substantial treatment risks.

Written and source-checked by the Jada Bascom FoundationSources checked Editorial standards

In-depth guide
Other names and abbreviations

SCD, HbSS disease, HbSβ0-thalassemia, sickling disorder, sickle cell anemia, sickle cell, Sickle-cell disease, Drepanocytosis

In short

  • Sickle cell disease is a group of inherited conditions. In these conditions, hemoglobin can make red blood cells less flexible, leading to anemia, pain and organ damage.
  • Care usually includes preventing infections, treating pain and a medicine called hydroxyurea. Some people also get blood transfusions.
  • For selected people, a transplant from a family or unrelated donor can change the disease course. In some countries, gene therapy using a person's own cells can do the same for selected people. Both have serious risks.
Jump to a section

Underlined words open a short explanation. See all terms

Where transplant fits

A can offer a potentially curative pathway for selected patients, using a suitable family or unrelated donor. Approved use the patient’s own modified cells and need no registry donor. Both approaches have eligibility requirements and serious risks.

Treatment depends on the exact diagnosis, disease stage, prior treatment and the person’s health.

Key facts

Who it affects
An inherited group of hemoglobin disorders affecting people worldwide. Genotype and individual course matter; sickle trait is distinct from sickle cell disease.
How common
About 100,000 people in the U.S.; about 1 in 365 Black or African American births and 1 in 16,300 Hispanic American birthsUnited States; CDC estimates. The 100,000 figure comes from two studies published in 2010 (CDC page last reviewed August 2026). Source: How common
How it is passed on
Autosomal recessive: a child is affected when both parents pass on a changed gene.
Cells used in a transplant
Donor marrow or other allogeneic blood-forming stem-cell grafts for transplantation; the patient’s own gene-modified stem cells for approved autologous gene therapies.
Where a donor fits
Cell or gene therapy options

The condition

What it is

Hemoglobin is the protein in red blood cells that carries oxygen. In sickle cell disease, the hemoglobin can clump into long strands when oxygen is low. Red cells then become stiff and can take a curved, sickle shape. These cells do not bend or move easily and can block blood flow. Damaged red cells, inflammation and poor blood flow in small blood vessels all cause harm.

There are several types of sickle cell disease, such as HbSS, HbSC and sickle beta-thalassemia. Sickle cell trait is different: a person with the trait carries one sickle gene and does not have the disease. The type matters, but people with the same type can still have very different symptoms.

Where sickle cell disease starts in the bloodSickle cell disease changes the hemoglobin inside red blood cells, so the red cells are the ones affected.Simplified illustration.

Marked as affected: red blood cells.

  • Blood stem cell, In the bone marrow
    • Myeloid line
      • Red blood cells, Affected
      • Platelets
      • Granulocytes
      • Monocytes
    • Lymphoid line
      • B cells
        • Plasma cells, Develop from B cells
      • T cells
      • NK cells, Natural killer cells
What the cells look like in sickle cell diseaseWhen oxygen is low, sickle hemoglobin can clump, so red cells turn stiff and curved and can block blood flow.Simplified illustration.

Two drawings of blood cells: first the usual shape, then, in sickle cell disease, red cells become stiff and can take a curved, sickle shape.

Usual shape

Round, flexible disc

In sickle cell disease

Stiff, curved sickle shape

Not every red cell takes the sickle shape, and real cells vary more than the three drawn here.

What causes it

Sickle cell disease is inherited. A child has it when both copies of the HBB gene, one from each parent, are changed and at least one change is the sickle change. Family testing and genetic counseling can explain what a result means for the family and for future children.

It occurs in people from many ancestries around the world. It is not defined by race, and it cannot be caught from another person.

How it can be inheritedIn autosomal recessive inheritance, a child is affected only when they inherit a changed copy of the gene from each parent.Simplified illustration.
Parents
  • Parent: Carrier: one changed copy, not affected
  • Parent: Carrier: one changed copy, not affected
Each child
  • 1 in 4: Affected, Two changed copies
  • 2 in 4: Carrier, One changed copy, like the parents
  • 1 in 4: Neither affected nor a carrier, Two working copies

The chances are the same for each pregnancy.

A child is affected when both copies of HBB carry a variant, at least one of them the sickle variant. Sickle cell trait is different from the disease.

  • Changed copy of the gene
  • Working copy

Symptoms and effects

Shortened red-cell survival causes anemia and jaundice. Reduced blood flow can cause acute pain episodes and contribute to chronic pain. The brain, lungs, kidneys, eyes, bones and other organs can be affected.

Complications include stroke, serious infection and acute chest syndrome, a lung illness that is a medical emergency. The US National Heart, Lung, and Blood Institute says it is important to know these complications and when to get emergency care.

Diagnosis and treatment

How sickle cell disease is diagnosed

In the United States, most people with sickle cell disease are found as newborns. All 50 states have programs, so nearly every baby is checked with a few drops of blood from a heel prick. The lab sorts the types of hemoglobin in the sample. The most used tests are high-performance liquid chromatography (HPLC), capillary electrophoresis and isoelectric focusing.

If a baby has sickle cell disease, a newborn screening follow-up team contacts the family directly. The baby is then retested to confirm the diagnosis. The same screen also finds babies with sickle cell trait, who carry one sickle gene but do not have the disease. Families of these babies are offered genetic counseling.

People who do not know whether they have the trait or the disease can have a blood test at any age. A gene test can show whether a person has one or two copies of the sickle gene. Testing is also possible before birth, as early as 8 to 10 weeks into pregnancy, using a sample of the fluid around the baby or of the placenta. It shows whether the baby has the sickle gene, but not how serious the symptoms will be.

A diagnosis names the type of sickle cell disease, but it cannot say how mild or severe one person's course will be.

How it is treated

Care includes vaccination, infection prevention, pain treatment and monitoring for organ complications. Hydroxyurea increases fetal hemoglobin and can reduce important complications. Transfusions are used for selected indications such as stroke prevention or severe acute illness; repeated transfusions may require iron management.

An allogeneic transplant uses another person’s . Matched sibling transplantation has a long evidence base, and unrelated or partially matched family donors may be considered with appropriate protocols. Suitability depends on disease burden, organ health, age, donor options and center experience.

In the United States, Casgevy uses gene editing to increase fetal hemoglobin, while Lyfgenia adds a modified beta-globin gene. Both use the patient’s own stem cells and are approved for people who have had pain crises caused by blocked blood flow. Since July 2026, Casgevy has been approved for people aged 2 and older; Lyfgenia is approved for people 12 and older. Neither requires a registry donor.

Gene therapy still requires stem-cell collection, chemotherapy and long-term follow-up. Risks include infertility and treatment toxicity; Lyfgenia carries a boxed warning for hematologic malignancy. Neither gene therapy nor donor transplant guarantees reversal of established organ injury.

How sickle cell disease can be treatedEveryday care prevents problems and eases pain, and for selected people a donor transplant or gene therapy can change the disease course.Simplified illustration.

Kinds of treatment described for sickle cell disease: supportive care, medicines, a donor stem cell transplant (for some people) and gene therapy with the person’s own cells (for some people).

After diagnosis, the options described here

  • Supportive care

    Vaccination, infection prevention, pain treatment and checks for organ problems, with transfusions for selected reasons.

  • Medicines

    Hydroxyurea raises fetal hemoglobin and can reduce serious complications.

  • Donor stem cell transplant, For some people

    Only some people are transplant candidates; a matched brother or sister has the longest track record.

    What a transplant involves

  • Gene therapy with the person’s own cells, For some people

    In the US, approved gene therapies change the person’s own stem cells and need no donor.

These are the kinds of treatment this page describes, not a plan. Which ones fit, in what order and whether they are combined differs from person to person.

When transplant specialists are usually consulted

U.S. transplant guidelines (NMDP and ASTCT) advise referring children with sickle cell disease who have a matched brother or sister, especially those under 13, to a transplant center at diagnosis. The same guidelines advise referral for all patients with a severe course, such as a stroke, frequent pain crises or organ damage.

Read the guidance

What a transplant involves

What a transplant involvesTiming and details differ by person and transplant center.Simplified illustration.
  1. Step 1

    : Finding a donor

    Relatives are tested first to see whether their tissue type (HLA) matches. If none match, the team searches donor registries and cord blood banks.

  2. Step 2

    : Conditioning

    Chemotherapy, sometimes with radiation, prepares the body for the new cells.

  3. Step 3

    : Transplant day, Day 0

    The donor’s cells are given through a vein, like a transfusion.

  4. Step 4

    : Engraftment

    The new cells settle in the marrow and start making blood cells, usually within weeks.

  5. Step 5

    : Recovery

    The immune system rebuilds over months. The team watches for infection, graft-versus-host disease (donor immune cells attacking the body) and relapse.

A transplant, step by step

Daily life and the donor’s role

Living with the condition

A care plan may include daily medicines, screening, transfusions and support for pain or fatigue. People can need help with education, employment, mental health and the transition from pediatric to adult services.

Availability differs between countries and health systems. Cost, referral, blood supply, specialist capacity and long-term follow-up can shape access to both routine and intensive treatment. A person’s options cannot be inferred from a national approval alone.

The donor’s role

An unrelated donor may be part of a specialist transplant plan, but family donors and gene therapies using a person’s own cells are also important options. No single donor route applies to everyone with sickle cell disease.

and donor suitability guide a search. Broader registry representation can expand options for patients needing unrelated transplantation. Access to specialist care, treatment and long-term follow-up also matters. Gene therapy uses the patient’s own cells.

Where transplant cells come fromWhich source a team considers depends on the condition, the person and who is available.Simplified illustration.

  • The person’s own cells

    Autologous transplant, no donor

    Collected from the person before treatment, then given back.

  • A relative

    Donor transplant (allogeneic)

    A brother or sister may be a full match. Parents and children can be half-matched donors.

  • An unrelated volunteer

    Donor transplant (allogeneic)

    Found through a donor registry.

  • Donated cord blood

    Donor transplant (allogeneic)

    Collected from a baby’s umbilical cord after birth and stored in a public bank.

Looking ahead

Looking ahead

Outlook for sickle cell disease

Sickle cell disease is lifelong, and its course differs a lot from person to person. The type matters. Sickle cell anemia (HbSS) is usually the most severe form, and HbS beta-zero thalassemia is usually severe too. HbSC and HbS beta-plus thalassemia are usually milder.

Good care changes the picture, especially for children. A yearly ultrasound of the blood vessels in the head (transcranial Doppler), with blood when needed, can help prevent stroke in children. A daily medicine called hydroxyurea helps prevent pain crises and other serious problems, and it is often started in babies as young as 9 months. Even so, CDC says life expectancy for people with sickle cell disease in the U.S. is more than 20 years shorter than average.

A donor transplant or gene therapy can change the outlook for some people. Transplants from a matched brother or sister have the longest track record. Results are best in younger patients, and the risk of dying after a is higher in teens and adults than in children. The figures below describe groups of people. They cannot predict how any one person will do.

About these numbers. Each one says which group of people it comes from, and the place and years where the source gives them. It describes what happened across that group, not what will happen to any one person. And a figure measured among people who had a transplant is not the same as the number of people who need one.

  • 52.6 yearsAverage life expectancy at birth

    94,616 people with sickle cell disease who had not had a transplant, U.S. Medicare and Medicaid enrollees, 2008–2016 (Blood Advances, 2023). People with private insurance were not included.

    Read the source: Average life expectancy at birth
  • 92.9%5-year survival after a matched-sibling transplant

    1,000 children and adults (median age 9) transplanted from an HLA-identical brother or sister at 106 centers in 23 countries, 1986–2013, reported to EBMT, Eurocord and CIBMTR (Blood, 2017). It was 95% for those under 16 and 81% for those 16 and older. Not a figure for everyone with the disease.

    Read the source: 5-year survival after a matched-sibling transplant

Life expectancy figures look back at care in past years. They do not include newer treatments such as gene therapy.

Common questions

Is sickle cell disease curable?

For some people, it can be. A blood stem cell transplant from a donor is a potentially curative treatment for selected patients. In the US, two approved gene therapies that use a person’s own modified stem cells are another option for some. Both approaches involve chemotherapy or radiation to prepare the bone marrow and weeks of specialized hospital care, and a transplant cannot always correct damage the disease has already caused. Everyday care centers on medicines such as hydroxyurea, infection prevention and, when needed, transfusions.

Is sickle cell disease inherited?

Yes. A child has sickle cell disease when they inherit two changed hemoglobin genes, one from each parent, and at least one of them is the sickle variant. It occurs in people of many ancestries around the world, and it cannot be caught from someone else. Family testing and genetic counseling can explain a family’s specific gene combination.

Is sickle cell trait the same as sickle cell disease?

No. Sickle cell trait means a person inherited one sickle gene from one parent and a typical hemoglobin gene from the other. People with the trait usually do not have the signs of the disease, but they can pass the sickle gene to their children. Sickle cell disease involves two changed hemoglobin genes, including at least one sickle gene, and can cause pain, infections, stroke and organ damage.

What are the first symptoms of sickle cell disease?

Early signs can include painful swelling of the hands and feet, called dactylitis; yellowing of the skin or eyes (jaundice); and extreme tiredness or fussiness from anemia. Most babies have no problems from the disease before they are about 5 or 6 months old. Symptoms vary from person to person and can change over time.

Can a brother or sister be the donor for sickle cell disease?

Yes, if the sibling is a close tissue (HLA) match and is suitable to donate. Transplants from matched brothers or sisters have a long track record in sickle cell disease. When no matched family donor exists, an unrelated registry donor or a partly matched relative may be considered under specialist protocols. Only some people with sickle cell disease are transplant candidates, and gene therapies use the patient’s own cells instead.

What is the life expectancy for someone with sickle cell disease?

It varies widely. In the U.S., people with sickle cell disease have lived much shorter lives than average. Those figures look back at past care. They do not include people who had a transplant or newer treatments such as gene therapy. The type of disease, access to specialist care, hydroxyurea and stroke screening all shape how one person does. The outlook section on this page gives the figures, with the groups they describe.

How does a bone marrow transplant treat sickle cell disease?

A transplant replaces the blood-forming cells that make sickle hemoglobin. First, chemotherapy or radiation clears space in the bone marrow (conditioning). Then healthy stem cells from a donor, usually a close relative whose tissue type (HLA) matches, are given through a vein. They travel to the marrow and make red blood cells that do not sickle. NHLBI reports success in about 90 of every 100 children whose donor is a matched relative. Risks include graft-versus-host disease, serious infections, infertility, seizures, a higher risk of some cancers later, and transplant failure. About 5 in 100 recipients under 16, and about 9 in 100 aged 16 or older, have died after transplant.

For your next appointment

Sickle cell disease

From the Jada Bascom Foundation disease library, jadabascomfoundation.org. Printed .

Questions to bring to your care team

  • Which type of sickle cell disease is this (for example HbSS or HbSC), and what does that mean for care?
  • Would HLA typing of brothers and sisters make sense, to see whether one could be a matched donor?
  • Is gene therapy, such as Casgevy or Lyfgenia, an option here, and how does it compare with a donor transplant at this center?
  • How could transplant or gene therapy affect fertility, and what can be done to protect it before treatment?
  • What is the goal of each treatment you are suggesting?
  • Where can our family find support during treatment?

A one-page list to take to the next appointment, with room for notes.

Supporting someone with a diagnosis

We respect your privacy. Unsubscribe anytime.

Support for patients and families

These independent organizations offer information and support. JBF is not affiliated with them.

Sources and further reading

  1. Sickle Cell Disease
    GeneReviews, University of Washington / NCBI Bookshelf, Accessed 2026-09-05
  2. Sickle Cell Disease: Treatment
    NHLBI, NIH, Accessed 2026-09-05
  3. CASGEVY: indication and current prescribing information
    FDA, Accessed 2026-09-05
  4. LYFGENIA: indication and current prescribing information
    FDA, Accessed 2026-09-05
  5. 2025 EBMT practice recommendations for transplantation and CAR-T
    EBMT, 2025
  6. FDA approves first gene therapy for young children with sickle cell disease (Casgevy, ages 2 and older)
    US Food and Drug Administration, 2026-07-01; accessed 2026-09-26
  7. Sickle Cell Disease: Health Effects
    NHLBI, NIH, Last updated 2024-08-22; accessed 2026-09-26
  8. Sickle cell disease
    MedlinePlus Genetics, US National Library of Medicine, 2024-03-14
  9. About Sickle Cell Disease
    CDC, 2026-08-07
  10. Sickle Cell Disease - Causes and Risk Factors
    NHLBI, NIH, 2024-08-20
  11. About Sickle Cell Disease
    Minnesota Department of Health, Updated 2026-09-11; accessed 2026-09-24
  12. Sickle Cell Disease - Diagnosis
    NHLBI, NIH, 2024-09-09
  13. Sickle Cell Disease - Symptoms
    NHLBI, NIH, 2024-08-20
  14. Data and Statistics on Sickle Cell Disease
    CDC, Updated 2024-05-14, reviewed 2026-08-07; accessed 2026-09-26
  15. Long-term survival with sickle cell disease: a nationwide cohort study of Medicare and Medicaid beneficiaries
    Blood Advances (Jiao and colleagues), 2023
  16. Sickle cell disease: an international survey of results of HLA-identical sibling hematopoietic stem cell transplantation
    Blood (Gluckman and colleagues), 2017
  17. Sickle Cell Disease: HCT consultation timing guidelines and outcomes
    NMDP, Accessed 2026-09-26

This information explains a condition and its treatments. It cannot diagnose an illness or recommend treatment for an individual. Your care team can explain how the evidence applies to you. Written and source-checked by the Jada Bascom Foundation. Each page lists the published sources it draws on.

Ways to help

Other patients are waiting for a match.

People with sickle cell disease may be treated with a transplant or, in some countries, a gene therapy. Many people with other blood cancers and blood disorders need a donor who is a stranger.

Help someone you love find a donor

When a donor transplant is planned, brothers and sisters are usually tested first. Each full sibling has about a one in four chance of being a full match.

Read the family guide

Join the registry

When no brother or sister matches, for this condition or another, the search turns to volunteer registries. JBF points you to the official registry that serves your country.

Join the registry Find your official registry

Support this work

Gifts to the Jada Bascom Foundation support donor-awareness education like this page, community outreach, drive planning and referrals to official registries.

Donate to JBF

More in the library

Keep learning

The flyer: STOP BLOOD CANCER set in tall letters over a dark plum page, a quote, and a QR code beside the words TEXT JADA TO 61474.One standing face of the table tent: the same headline and quote on the left, a large QR code on the right.

Take it off the screen

Print it. Put it where people already stand.

A coffee counter, a church foyer, a break room, a race table. Every sheet carries the code that opens Jeana’s walk, and a number to text for anyone who would rather not scan — no app, no wifi, nothing to hand back.

Everything else for running a drive

Rather be the one at the table?

Host a registration drive at your school, work or place of worship, raise funds, or lend a skill. Tell us what you have in mind and we will help you plan it.

Ways to volunteerHost a registration drive