Senior Consultant, Pediatric Hemato-Oncology and Bone Marrow Transplant, Artemis Hospitals, Gurugram, India
Part 2 of 9 in Sickle Cell Disease and Bone Marrow Transplant
Why Sickle Cell Disease Affects Every Organ in the Body
September 2, 2026
The entire disease traces back to a single amino acid substitution. A single change in the beta-globin gene, glutamine replaced by valine, converts normal adult hemoglobin into hemoglobin S. That one molecular change is the sole mechanism behind everything that follows.
How the disease is inherited
Two carriers, both AS, each carry one copy of the sickle gene without symptoms themselves. When two AS carriers have a child, there is a 25% chance the child will inherit two copies of the gene and develop full-blown SS sickle cell disease. Knowing carrier status before pregnancy, through testing of both partners, is the only way to prevent this outcome, and the same logic applies to thalassemia carrier screening.
How sickling damages organs, one by one
Hemoglobin S strips red blood cells of their normal flexibility. They become sticky, tangle with each other, and clog small blood vessels. Since every organ depends on blood supply, every organ is a potential target, and the damage recurs across a patient's lifetime rather than happening once.
Pain crisis and acute chest syndrome
A pain crisis feels like the bones and joints are breaking, caused by vessel occlusion, and can be triggered by something as ordinary as a change in weather, cold exposure, stress, or infection. When the lungs are affected, the result is acute chest syndrome, a pneumonia-like picture with low oxygen, rapid breathing, an abnormal chest X-ray, and frequently an ICU admission.
Brain, spleen, and kidney damage
In the brain, sickling causes silent infarcts or full strokes that can leave a patient wheelchair-bound for life; smaller, repeated episodes short of overt stroke show up instead as poor school performance and weak academic skills. The spleen loses function after repeated occlusion, typically by four to five years of age, leaving patients vulnerable to encapsulated organisms like Staphylococcus aureus, Haemophilus influenzae, and Neisseria meningitidis. The kidney suffers the same cumulative damage: one 34-year-old transplant candidate arrived with only one functioning kidney, at 60 to 70% capacity, entirely because of years of sickling.
Bone, eye, and heart involvement
Avascular necrosis of the femoral head is common enough that many sickle cell patients travel to India specifically for hip or joint replacement. The eyes can bleed, the heart can weaken, and other life-threatening complications accumulate on top of these. The disease touches bone, heart, kidney, spleen, lung, eye, and brain, which is why it is now described as sickle cell disease rather than simply sickle cell anemia.
This article is based on a Jivo Masterclass session conducted by Dr. Arun Singh Danewa, Senior Consultant, Pediatric Hemato-Oncology and Bone Marrow Transplant, Artemis Hospitals, Gurugram. The article has been summarised with the assistance of an AI tool from the original masterclass recording. Watch the full Masterclass recording
Looking for a sickle cell disease or bone marrow transplant consultation or a second opinion? Get in touch with the Jivo team
This guide is based on a live Jivo Masterclass — Dr. Arun Singh Danewa taught doctors across Africa on September 2, 2026.
FROM THE LIVE Q&A
Moderator
If disease-modifying drugs continue to improve, will that eventually eliminate the need for bone marrow transplant?
Dr. Arun Singh Danewa
No. These drugs do not hit the primary pathology, the sickling process itself. They can reduce pain symptoms and severity, but the silent chronic organ damage keeps progressing underneath. Only bone marrow transplant and gene therapy correct the underlying disease, so a patient who can access and afford curative therapy should pursue it; supportive therapy remains the best option only where curative treatment is out of reach.
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Frequently Asked Questions
Over a lifetime, would supportive therapy end up costing more than a bone marrow transplant?▼
Yes, cumulatively the costs converge. Patients in their mid-thirties frequently say they would accept any transplant risk just to be rid of the disease. Adding up a lifetime of hospitalizations and medications produces a total broadly similar to the cost of transplant, the real difference is timing: transplant requires the full sum upfront in a short window, while supportive care is paid in smaller, less visible installments over decades.
How many times can one person be a bone marrow donor?▼
Usually a maximum of two times in a lifetime, under blood bank regulations in most countries. The minimum gap between two donations should be six months, occasionally reduced to three months in a life-threatening situation, though six months to a year is recommended. Most Indian regulations do not permit bone marrow donation beyond two times.
If two siblings both have sickle cell disease and one sibling is a full-match donor, can that one donor's harvest be used for both patients?▼
Yes, this is done in practice. Since the minimum stem cell dose is 3 million cells per kilogram of the recipient's weight, a larger harvest can be divided into two doses for two patients. Where families want to proceed with one transplant first and the second once funds are arranged, half the dose is used immediately and the rest is cryopreserved for the second transplant later, sometimes with additional stimulating injections used to boost the donor's total yield.
If a patient undergoes a successful bone marrow transplant, grows up, and has children of their own, is the sickle cell inheritance chain broken for the next generation?▼
No. Transplant replaces the blood-forming stem cell system, not the gene itself; the reproductive organs still carry the SS gene. The post-transplant patient will transmit one sickle gene to their offspring, and if their partner is also a carrier, their child can still be born with sickle cell disease. Families need to be counseled that both the patient and their partner should be tested once the child is grown and ready to have children of their own.
Is it safe to do a bone marrow transplant in a child between one and two years old, when they cannot yet express symptoms during the process, or is it better to wait until they can?▼
Transplant is safe from one year of age; the literature supports one year as the minimum, and the child's inability to verbally express discomfort is not the limiting factor, since transplants are routinely done for leukemia in infants as young as six to eight months when it is a do-or-die situation. What matters is that the body can tolerate the immunosuppression and the physical toll of the transplant, and that organs are sufficiently mature. One year is workable, but the preferred window remains two to five years, where outcomes are excellent.
Why is sickle cell disease no longer just called anemia?▼
Because it damages nearly every organ system through repeated vessel occlusion, not just the blood. It causes pain crises, stroke, lung disease, kidney failure, bone necrosis, and spleen dysfunction over a patient's lifetime.
What is the inheritance risk when both parents are sickle cell carriers?▼
When both parents are AS carriers, there is a 25% chance with each pregnancy that the child will inherit two copies of the sickle gene and develop full sickle cell disease.
In This Series: Sickle Cell Disease and Bone Marrow Transplant
- 1.Sickle Cell Disease and Bone Marrow Transplant
- 2.Why Sickle Cell Disease Affects Every Organ in the Body
- 3.Supportive Care vs Cure: The Two Tracks of Sickle Cell Treatment
- 4.Finding a Donor: HLA Matching and Haploidentical Transplant in Sickle Cell
- 5.Conditioning and Fertility: What Happens Before a Sickle Cell Transplant
- 6.Stem Cell Collection and the Right Age for Sickle Cell Transplant
- 7.Engraftment and Chimerism: How Doctors Know a Sickle Cell Transplant Is Working
- 8.Gene Therapy and Drug Treatments: The Non-Transplant Options for Sickle Cell
- 9.Cost, Outcomes, and Genetics After a Sickle Cell Cure