Both parents are Wilson disease carriers — what are the odds for our child?

The short answer is one in four. When both parents carry one working copy and one faulty copy of the ATP7B gene, every pregnancy faces the same probability: a 25% chance the child will have Wilson disease, a 50% chance the child will be a carrier (healthy, like you), and a 25% chance the child inherits two working copies and carries no risk at all.¹ These odds apply fresh to every pregnancy — they do not “even out” across siblings.

Why genetics works this way

Wilson disease is autosomal recessive.² “Autosomal” means the gene sits on one of the 22 non-sex chromosomes, so boys and girls are equally affected. “Recessive” means a person only develops the disease when both copies of ATP7B are faulty. If even one working copy is present, it produces enough of the ATP7B copper-transport protein to prevent copper accumulation.

You and your husband each have one working copy and one faulty copy — a pairing geneticists call heterozygous. When you conceive, each of you randomly passes on one of your two copies. There are four equally likely combinations:

Copy from you	Copy from husband	Child’s status
Working	Working	Unaffected, not a carrier
Working	Faulty	Carrier (healthy)
Faulty	Working	Carrier (healthy)
Faulty	Faulty	Wilson disease

Each row has the same 25% probability. The table resets for every pregnancy.

“Carrier” does not mean sick

Carriers have one working ATP7B gene and one faulty one. Historically they were assumed to be completely healthy. A 2025 pilot study found subtle differences in copper metabolism markers among some carriers compared to non-carriers,³ but this is early research with a small sample and no clinical consequence has been established. Carriers do not develop Wilson disease, do not require treatment, and live normal lives. The brief mentions this line of research exists so you can discuss it with a geneticist if you want — not because it should alarm you.

The 25% risk in practical terms

It helps to think about what these odds mean over a full family. If you had four children, on average one would have Wilson disease, two would be carriers, and one would be entirely unaffected — but “on average” does not mean the outcomes spread that neatly in any real family. You could have three children with Wilson disease, or none. Each pregnancy is an independent draw.

For many couples this is the moment that makes family screening feel urgent and real. If a child does receive a Wilson disease diagnosis, catching it before symptoms appear gives treatment the best possible starting point — this is exactly the scenario where early diagnosis changes everything.¹

Testing options before and after pregnancy

Before pregnancy — preimplantation genetic testing (PGT) Couples who know both partners are carriers can pursue in vitro fertilization (IVF) with PGT. Embryos are biopsied before transfer and only those without two faulty copies are selected. This eliminates the 25% risk but requires IVF, which has its own costs, success rates, and emotional weight. A genetic counsellor and reproductive medicine specialist together can help you weigh whether this fits your situation.

During pregnancy — prenatal diagnosis Chorionic villus sampling (CVS, around weeks 10–13) or amniocentesis (around weeks 15–18) can test fetal DNA for the specific ATP7B variants you both carry. This tells you definitively whether the fetus has Wilson disease. What you do with that information is your decision; the testing itself simply provides clarity.

After birth — newborn or early childhood testing Because you know both of your variants, any child you have can be tested from birth with a simple blood-based genetic test. If a child has two faulty copies, treatment can begin — and prevention started early, before any copper accumulation becomes symptomatic, gives the best long-term outcomes.² Current guidelines support genetic testing of at-risk family members as soon as the parental variants are known.⁴

Do you know your exact variants?

Wilson disease is caused by more than 600 different mutations in ATP7B, and what matters for family testing is knowing your specific mutations — not just that you “carry Wilson disease.”⁵ If either of you has not had full sequencing of ATP7B, ask your hepatologist or a genetics service to complete it. Without knowing the exact variants, prenatal or newborn testing cannot be designed correctly.

What to ask your genetics team

A few questions worth raising at your next appointment:

• “Have both our full ATP7B sequences been documented, or only one variant per person?”
• “Are we candidates for preimplantation genetic testing, and which fertility centres in our area offer it?”
• “If we proceed with natural conception, at what age and with what test should we screen each child?”
• “Is there a Wilson disease specialist or metabolic genetics clinic you would refer us to?”

Your GP or hepatologist can refer you to a clinical genetics service — this does not need to be sorted alone.

One last thing about your own health

Carriers do not develop Wilson disease and almost certainly do not need monitoring or treatment. If you have never had your own copper status formally checked, it is worth mentioning to your doctor simply so you have a documented baseline — not because there is any known risk, but because having the data on file is useful if questions come up later.⁴

This page is patient education, not medical advice. Genetics in the context of family planning involves personal decisions that deserve a conversation with both a Wilson disease specialist and a certified genetic counsellor who knows your full family history.

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