Hematology

Is PNH Hereditary? What This Means for Your Family

At a Glance

Classic paroxysmal nocturnal hemoglobinuria (PNH) is not hereditary. Its PIGA mutation develops after birth in a blood-forming stem cell, not in sperm or eggs, so it cannot be passed to children; pregnancy still requires specialist planning because complications can increase.

The short answer is no. Classic paroxysmal nocturnal hemoglobinuria (PNH) is an acquired condition, not a hereditary one. You cannot pass it down to your biological children, and they are not considered to have an increased risk of developing it because of your diagnosis ^[1]^[2].

When a doctor explains that PNH is caused by a genetic mutation, it is completely natural to worry about what that means for your family. However, the genetic change that causes classic PNH is an acquired somatic mutation ^[3]. This means the mutation happened at some point after you were born—usually without any known cause or trigger—rather than being passed down from your parents. It is not caused by anything you did, and it cannot be passed on to your offspring.

What This Means For Your Family and Pregnancy

Your Children: Routine testing of your children for PNH is not necessary just because you have classic PNH. Because the condition does not run in families, you do not need to worry about transmitting the disease to them ^[1]^[2].

Pregnancy Planning: While your children will not inherit PNH, pregnancy itself requires very careful specialist planning if you have PNH. Pregnancy and the postpartum period can significantly increase the risk of PNH complications, such as blood clots (thrombosis) and the destruction of red blood cells (hemolytic anemia) ^[4]^[5]^[6]. These risks mean that any pregnancy should be planned alongside your hematologist and a high-risk maternal-fetal medicine team ^[7]. You should never stop or change PNH medications or blood thinners without direct medical guidance, as treatments like complement inhibitors can be beneficial during pregnancy but must be carefully managed by experts ^[8]^[9].

Understanding Your Genetic Mutation

In classic PNH, a mutation arises in a specific gene called the PIGA gene ^[1].

Normally, the PIGA gene is responsible for building a tiny anchor (the GPI anchor) that attaches certain protective proteins—such as CD55 and CD59—to the surface of your cells ^[10]^[11]. These proteins act like shields, protecting your blood cells from being attacked by your body’s own complement system (a part of your immune system). When the PIGA mutation occurs, those protective shields are missing, leaving your red blood cells vulnerable to destruction ^[2]^[12].

Crucially, this PIGA mutation arises in a single blood-forming stem cell in your bone marrow, and is carried by the clone of blood cells descended from it ^[1]^[3]. It does not affect your reproductive cells (sperm or eggs).

Inherited vs. Acquired Conditions

To help put your mind at ease, it is helpful to understand the difference between the two types of mutations:

Inherited (Germline) Mutations: These are present from conception. They exist in every single cell of a person’s body, including their reproductive cells. Because they are in reproductive cells, they can be passed on to the next generation.
Acquired (Somatic) Mutations: These occur after a person is born and only affect specific tissues in the body—in the case of PNH, only the blood-forming cells. Because acquired mutations are missing from sperm and egg cells, they cannot be inherited by your children ^[1]^[13].

Note: There are extremely rare, inherited disorders linked to the PIGA gene (such as PIGA-CDG) that are completely different from classic PNH ^[14]^[15]. These rare inherited conditions typically present in early childhood with severe developmental and neurological issues ^[14]^[16]. They should not be confused with the typical, acquired PNH that develops in blood-forming cells.

Common questions in this guide

Is classic PNH an inherited condition?

No. Classic PNH develops after birth when a mutation occurs in a blood-forming stem cell, rather than being inherited from a parent. Because the mutation is not present in sperm or egg cells, classic PNH is not passed through families.

Can a person with PNH pass it to their children?

Classic PNH cannot be passed to biological children, and a parent's diagnosis does not generally increase a child's risk of developing classic PNH. Routine PNH testing of children is not needed solely because a parent has classic PNH.

Why is PNH called genetic if it is not hereditary?

PNH involves a change in the PIGA gene, but that change is acquired after birth in one blood-forming cell. It is carried by the blood cells that descend from that cell and is not present in the reproductive cells that could pass genetic changes to a child.

Can someone with PNH have a safe pregnancy?

Pregnancy and the postpartum period can increase the risk of complications such as blood clots and destruction of red blood cells. Pregnancy should be planned and monitored by a hematologist and a high-risk maternal-fetal medicine team, with treatment decisions made by those specialists.

Does classic PNH require genetic testing for my family?

Classic PNH usually does not require genetic testing of children because its mutation is acquired in blood-forming cells. Genetic counseling may be considered when doctors suspect a rare inherited PIGA-related disorder, especially when symptoms began in early childhood or include severe developmental or neurological problems.

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Related questions

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Curated prompts to bring to your next appointment.

1.Since I have PNH, what specific precautions or specialist planning would I need if I were to become pregnant?
2.If I am already on anticoagulants or complement inhibitors, how might pregnancy affect my treatment plan?
3.Given my specific diagnosis and health history, is there any reason to undergo genetic counseling, or does my classic PNH diagnosis make that unnecessary?
4.Does my PNH diagnosis involve any other bone marrow conditions (like aplastic anemia) that I should consider when thinking about family planning?

References (16)

1
Paroxysmal nocturnal hemoglobinuria: role of the complement system, pathogenesis, and pathophysiology.
Bektas M, Copley-Merriman C, Khan S, et al.
Journal of managed care & specialty pharmacy 2020; (26(12-b Suppl)):S3-S8 doi:10.18553/jmcp.2020.26.12-b.s3.
PMID: 33356782
2
Molecular genetics, biochemistry, and biology of PNH.
Kinoshita T
[Rinsho ketsueki] The Japanese journal of clinical hematology 2017; (58(4)):353-362 doi:10.11406/rinketsu.58.353.
PMID: 28484166
3
Multidisciplinary clinical management of paroxysmal nocturnal hemoglobinuria.
Sahin F, Ozkan MC, Mete NG, et al.
American journal of blood research 2015; (5(1)):1-9.
PMID: 26171279
4
Pregnancy outcomes of patients with paroxysmal nocturnal hemoglobinuria treated with eculizumab: a Japanese experience and updated review.
Miyasaka N, Miura O, Kawaguchi T, et al.
International journal of hematology 2016; (103(6)):703-12 doi:10.1007/s12185-016-1946-x.
PMID: 26857155
5
[Management of pregnancy and delivery in patients with paroxysmal nocturnal hemoglobinuria].
Usuki K
[Rinsho ketsueki] The Japanese journal of clinical hematology 2015; (56(7)):785-94 doi:10.11406/rinketsu.56.785.
PMID: 26251141
6
[Rare case of a pregnancy in a woman with paroxysmal nocturnal hemoglobinuria. Case report].
Horányi D, Várkonyi A, Nagy GR, et al.
Orvosi hetilap 2016; (157(23)):916-8; quiz 919-20 doi:10.1556/650.2016.30430.
PMID: 27233835
7
[Paroxysmal nocturnal hemoglobinuria during pregnancy: a case report and literature review].
Wang W, Wang XQ
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 2024; (45(9)):861-863 doi:10.3760/cma.j.cn121090-20240411-00137.
PMID: 39414612
8
Paroxysmal nocturnal haemoglobinuria in pregnancy-a systematic review with meta analysis.
Manning JE, Ciantar E, Griffin M, Kelly RJ
Annals of hematology 2025; (104(4)):2517-2525 doi:10.1007/s00277-025-06353-7.
PMID: 40244439
9
Pregnancy outcomes in women receiving eculizumab for the management of paroxysmal nocturnal haemoglobinuria.
Manning JE, Anderson RM, Hill A, et al.
Obstetric medicine 2022; (15(1)):45-49 doi:10.1177/1753495X211019899.
PMID: 35444730
10
A Novel Mutation in PIGA Associated with Multiple Congenital Anomalies-Hypotonia-Seizure Syndrome 2 (MCAHS2) in a Boy with a Combination of Severe Epilepsy and Gingival Hyperplasia.
Neuhofer CM, Funke R, Wilken B, et al.
Molecular syndromology 2020; (11(1)):30-37 doi:10.1159/000505797.
PMID: 32256299
11
A novel PIGA mutation in a family with X-linked, early-onset epileptic encephalopathy.
Kim YO, Yang JH, Park C, et al.
Brain & development 2016; (38(8)):750-4.
PMID: 26923721
12
Hematopoietic stem cell transplantation for patients with paroxysmal nocturnal hemoglobinuria previously treated with eculizumab: a retrospective study of 21 patients from SFGM-TC centers.
Vallet N, de Fontbrune FS, Loschi M, et al.
Haematologica 2018; (103(3)):e103-e105 doi:10.3324/haematol.2017.182360.
PMID: 29269526
13
A likely pathogenic variant putatively affecting splicing of PIGA identified in a multiple congenital anomalies hypotonia-seizures syndrome 2 (MCAHS2) family pedigree via whole-exome sequencing.
Yang J, Wang Q, Zhuo Q, et al.
Molecular genetics & genomic medicine 2018; (6(5)):739-748 doi:10.1002/mgg3.428.
PMID: 29974678
14
Lessons learned from 40 novel PIGA patients and a review of the literature.
Bayat A, Knaus A, Pendziwiat M, et al.
Epilepsia 2020; (61(6)):1142-1155 doi:10.1111/epi.16545.
PMID: 32452540
15
Drosophila models of phosphatidylinositol glycan biosynthesis class A congenital disorder of glycosylation (PIGA-CDG) mirror patient phenotypes.
Thorpe HJ, Owings KG, Aziz MC, et al.
G3 (Bethesda, Md.) 2024; (14(3)) doi:10.1093/g3journal/jkad291.
PMID: 38124489
16
The genotypic and phenotypic spectrum of PIGA deficiency.
Tarailo-Graovac M, Sinclair G, Stockler-Ipsiroglu S, et al.
Orphanet journal of rare diseases 2015; (10()):23 doi:10.1186/s13023-015-0243-8.
PMID: 25885527

This page explains whether classic PNH can be inherited for informational purposes only and does not replace medical advice. Discuss pregnancy planning, medications, and genetic concerns with your hematologist and maternal-fetal medicine team.