An Overview of Paroxysmal Nocturnal Hemoglobinuria in Young Adults By: Jia Reyes

Introduction

Medicine has transformed countless lives through scientific interventions, yet thousands of diseases

continue to receive insufficient public recognition due to their rarity. Among these is Paroxysmal

Nocturnal Hemoglobinuria (PNH), a rare acquired blood disorder that affects the body's ability to

produce healthy blood cells and protect them from destruction. Although its prevalence is low, PNH can

lead to serious complications, including chronic hemolysis, bone marrow failure, kidney damage, and

life-threatening blood clots if left undiagnosed or untreated (Oliver & Patriquin, 2023).

PNH develops due to an acquired mutation in the PIGA gene within hematopoietic stem cells, resulting in

the absence of protective proteins that typically shield blood cells from the body's complement system.

Without these proteins, red blood cells become vulnerable to premature destruction, leading to a wide

range of symptoms that often interfere with a person's lifestyle. While advances in complement-targeted

therapies have significantly improved patient outcomes over the past two decades, early diagnosis

remains a challenge because many of the disease's symptoms resemble those of more common conditions

(Kelly et al., 2025).



Although PNH is typically identified in adults between the ages of 30 and 40 years old, it can also occur

in adolescents and young adults as they experience significant milestones such as education, career goals,

and independence (Zorina et al., 2026). Managing a rare chronic condition during these formative years

can introduce predicaments that extend beyond physical symptoms, affecting emotional well-being, daily

activities, and future ambitions.Molecular Mechanisms and Disease Pathogenesis

The development of Paroxysmal Nocturnal Hemoglobinuria is rooted in a complex interaction between

genetic mutations, hematopoietic stem cells, and immune regulation. Unlike inherited genetic disorders,

PNH is an acquired condition caused by somatic mutations that occur in hematopoietic stem cells within

the bone marrow. The primary genetic abnormality involves the phosphatidylinositol glycan class A

(PIGA) gene, which is crucial for the formation of glycosylphosphatidylinositol (GPI) anchors. These

anchors function as attachment points for several proteins that protect blood cells from immune-mediated

destruction (Brodsky, 2022).

Scientists have demonstrated that the loss of GPI-anchored proteins, particularly CD55 and CD59, plays

a central role in PNH progression. CD55 normally regulates complement activation by accelerating the

breakdown of complement components, while CD59 prevents the formation of the membrane attack

complex (MAC), which is a structure responsible for creating pores in cell membranes. Without proper

protection from these proteins, affected blood cells become highly sensitive to complement-mediated

attacks, resulting in continuous intravascular hemolysis (Kelly et al., 2025).

However, recent research suggests that PNH is more than simply a disorder of red blood cell destruction.

Studies have shown that the survival advantage of PNH clones within the bone marrow may be influenced

by immune-mediated selection. Under certain conditions, normal hematopoietic cells may be damaged by

immune attacks, allowing abnormal PNH cells that lack GPI-linked proteins to expand because they are

less vulnerable to specific immune mechanisms (Brodsky, 2022). This finding has helped researchers

better understand why PNH clones can persist and increase over time.

Furthermore, complement activation contributes not only to hemolysis but also to inflammation and

thrombosis, two major complications of the disease. Excessive complement activity can activate platelets

and give rise to abnormal clot formation, explaining why patients with PNH have an increased risk of

life-threatening thrombosis, including clots occurring in unusual locations such as abdominal veins

(Oliver & Patriquin, 2023).

PNH Education & Involvement

It is in our nature to respond more strongly to what feels close to us. The struggles we witness in our own

communities often feel more urgent than those happening beyond our immediate view. When suffering

belongs to people we have never met, in places we have never been, or in conditions we have never

experienced, it can become easier to look away. Science describes this as psychological distance, the

tendency for unfamiliar or distant experiences to feel less emotionally immediate (Wahid et al., 2026). Yet

distance does not lessen the reality of another person’s life.Rare diseases often exist in this space of being overlooked. Because they affect fewer individuals, they

may receive less attention, fewer resources, and less recognition; even less interest from researchers and

scientists. However, the value of a life has never been determined by how many people share the same

struggle. Even if only 1% of the population lives with a condition such as Paroxysmal Nocturnal

Hemoglobinuria, that 1% is still composed of people—each with a name, an ambition, and a future they

wish to live. A number may appear small on paper, but to the person living within that number, it

represents an entire world.

Our society is connected by more than proximity; we are connected by our shared humanity. Caring for

illnesses we may never encounter is an acknowledgment that suffering does not need to belong to us

personally before it deserves our attention. Awareness is not only about learning the science behind a

disease, but it is also about refusing to let unfamiliarity become indifference

Conclusion

Paroxysmal Nocturnal Hemoglobinuria is a rare acquired blood disorder caused by mutations in the PIGA

gene, leading to complement-mediated destruction of blood cells and complications such as hemolytic

anemia, thrombosis, and bone marrow dysfunction. Advances in diagnostic techniques, particularly flow

cytometry, have improved the identification of PNH, while complement-targeted therapies such as C5 and

C3 inhibitors have significantly improved patient outcomes and quality of life (Kelly et al., 2025; Gandhi

et al., 2026).

Despite major progress in treatment, continued research remains necessary to address remaining

challenges, including treatment accessibility, long-term disease management, and the development of

more effective therapies. Increasing awareness among healthcare professionals and the public is also

essential for promoting earlier diagnosis and improving outcomes for individuals living with PNH.

Continued scientific investigation will further enhance understanding of the disease and support the

development of improved therapeutic strategies.

Sources

Brodsky, R. A. (2021). How I treat paroxysmal nocturnal hemoglobinuria. Blood, 137(10), 1304–1309.

https://ashpublications.org/blood/article/137/10/1304/475031/How-I-treat-paroxysmal-nocturnal-hemoglo

binuria

Hill, A., DeZern, A. E., Kinoshita, T., & Brodsky, R. A. (2017). Paroxysmal nocturnal haemoglobinuria.

Nature Reviews Disease Primers, 3, Article 17028. https://www.nature.com/articles/nrdp201728

Oliver, M., & Patriquin, C. J. (2023). Paroxysmal nocturnal hemoglobinuria: Current management, unmet

needs, and recommendations. Journal of Blood Medicine, 14, 613–628.

https://www.dovepress.com/paroxysmal-nocturnal-hemoglobinuria-current-management-unmet-needs-an

d-peer-reviewed-fulltext-article-JBMParker, C., Omine, M., Richards, S., Nishimura, J., Bessler, M., Ware, R., Hillmen, P., Luzzatto, L.,

Young, N., Kinoshita, T., Rosse, W., & Socié, G. (2005). Diagnosis and management of paroxysmal

nocturnal hemoglobinuria. Blood, 106(12), 3699–3709.

https://ashpublications.org/blood/article/106/12/3699/109767/Diagnosis-and-management-of-paroxysmal-

nocturnal

Risitano, A. M., Marotta, S., Ricci, P., Sica, M., Kulasekararaj, A. G., Calabrese, M., Sessa, M., &

Schrezenmeier, H. (2016). Anti-complement treatment for paroxysmal nocturnal hemoglobinuria: Time

for proximal complement inhibition? Blood Transfusion, 14(6), 487–495.

https://www.bloodtransfusion.it/public/pre2018archives/2016/BloodTransfus2016

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Wahid, S. M., Dawes, C. T., & Light, A. E. (2026). Out of reach, out of mind? Mechanisms of

psychological distance and emotional reactions to tragedy abroad. Psi Chi Journal of Psychological

Research, 31(1),

59–71.https://www.psichi.org/page/JN2026-016-Mechanisms-Of-Psychological-Distance-And-Emotional

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