Sperm donor unknowingly carried rare cancer gene—10 of his children now diagnosed

Time of India

26-05-2025

A sperm donor whose genetic material was used to conceive at least 67 children across Europe unknowingly carried a rare cancer-causing gene mutation, and now 10 of those children have developed cancer.
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How the case was discovered?
The troubling discovery centers around a mutation in the TP53 gene, commonly associated with Li-Fraumeni syndrome, one of the most severe inherited cancer predisposition syndromes. The donor's sperm, distributed by the European Sperm Bank, was used between 2008 and 2015. At the time of donation, the mutation was not known to be linked to cancer and would not have been detectable using standard screening.
The issue came to light after two families, unaware of each other, contacted their fertility clinics following cancer diagnoses in their children.
Subsequent analysis confirmed the TP53 variant in the donor's sperm, prompting further investigation. Geneticists and pediatric departments across eight European countries began testing other families who had used the same donor, eventually identifying 67 children from 46 families.
Of these, 23 carried the variant, 10 of whom have been diagnosed with cancer, including cases of leukemia and non-Hodgkin lymphoma.
A hidden mutation and a trail of diagnoses
Dr. Edwige Kasper, a biologist at Rouen University Hospital in France, presented the case at the European Society of Human Genetics conference in Milan. 'We need to have a European limit on the number of births or families for a single donor,' she said. 'We can't do whole-genome sequencing for all sperm donors – I'm not arguing for that. But this is the abnormal dissemination of genetic disease. Not every man has 75 children across Europe.
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Kasper said her team analyzed the mutation using population and patient databases, computer prediction tools, and functional trial data. 'I analysed the variant using population and patient databases, computer prediction tools and the results of functional trials and came to the conclusion that the variant was probably cancer-causing and that children born from this donor should receive genetic counselling,' she explained.
Children with the TP53 mutation are now advised to undergo regular whole-body MRIs, brain scans, and abdominal ultrasounds. As they grow older, breast MRIs are also recommended.
Case sparks concerns in the fertility industry
The European Sperm Bank confirmed that over 67 children were conceived using the donor's sperm but declined to give an exact number. Its spokesperson, Julie Paulli Budtz said: 'We are deeply affected by this case.' She added: 'We welcome continued dialogue on setting an internationally mandated family limit and have advocated for this on several occasions.
This is also why we have proactively implemented our own international limit of 75 families per donor.
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Budtz also emphasized the difficulty in catching such rare mutations in advance. 'It is scientifically simply not possible to detect disease-causing mutations in a person's gene pool if you don't know what you are looking for,' she said.
Still, Kasper expressed concern about the lack of transparency. 'Is 67 the total? It's a really good question that I've asked the sperm bank.
They didn't want to tell me the denominator of the births for this donor,' she said.
As more donor-conceived children continue to be diagnosed, the case underscores the urgent need for cross-border cooperation and reform in the fertility industry, before another family unknowingly inherits more than they bargained for.