Asperm donor with a rare genetic mutationlinked to an increased risk of developingcancerfathered at least 197 children across Europe, some of whom have already died from the disease, according to a new investigation.
The donor, who is himself healthy, had a rare mutation in a gene named TP53, which is likely to cause Li-Fraumeni syndrome, a rare disorder that increases a person's risk of developing cancer. He was unaware when he made the sperm donations that he was affected by the mutation.
In May, CNN reported that the man had fathered at least 67 children in eight European countries, but a major investigation published by news outlets Wednesday has shown that the number of affected children is in fact far higher than previously thought.
According to theBBC, which is one of 14 European public service broadcasters involved in the investigation, the new figure is the product of freedom of information requests and interviews with doctors and patients.
The man donated to a single private sperm bank in Denmark named the European Sperm Bank (ESB), but his sperm was later used by 67 clinics in 14 different countries. The final number of affected children may be higher still, "as data has not been obtained from all countries," the BBC added.
It is not known how many of these children have inherited the genetic mutation, but only a small proportion of those who have done so will avoid developing some form of cancer in their lifetimes. People with the condition have a 90% chance of developing one or more kinds of cancer by age 60, and around 50% do so before age 40, according to theCleveland Clinic.
Edwige Kasper, a biologist at Rouen University Hospital in France, identified an initial 67 children during a presentation at the annual conference of the European Society of Human Genetics in May.
At the time, she said 10 of the children had been diagnosed with cancers such as brain tumors and Hodgkin lymphoma, and another 13 were carrying the gene but had not yet developed a cancer.
They will require regular medical examinations due to their increased risk of developing cancer, and have a 50% chance of transmitting it on to their own children, Kasper said back in May.
On Wednesday, Clare Turnbull, professor of cancer genetics at the Institute of Cancer Research, London, told CNN that "Li Fraumeni syndrome is a devastating diagnosis to impart to a family."
"There is a very high risk of cancer throughout the lifetime," she added, "with a sizeable risk of childhood-onset cancers."
The case "represents a highly unfortunate coincidence of two exceptionally unusual events: that the donor's sperm carry mutations for an extremely rare genetic condition affecting fewer than 1 in 10,000 people and that his sperm has been used in the conception of such an extraordinarily large number of children," she added.
Mary Herbert, professor of reproductive biology at Monash University in Melbourne, Australia, said the investigation "highlights an urgent need for more comprehensive genetic screening of sperm donors and for strict cross-border controls on the number of children conceived from a single donor."
"It is staggering that a single donor was used to conceive almost 200 children across a relatively small number of European countries," she told CNN in a statement sent via the Science Media Centre on Wednesday.
Julie Paulli Budtz, a spokeswoman for the European Sperm Bank (ESB), told CNN that the company is "deeply affected by the case and the impact that the rare TP53 mutation has on a number of families, children and the donor."
"They have our deepest sympathy," she added.
"ESB tests and performs an individual medical assessment of all donors in full compliance with recognized and scientific practice and legislation," Budtz said, adding that the ESB supports calls for a limit on the number of children that are allowed to be born using a single donor.
"The legislation on these areas is complex, with many and often conflicting considerations, and the implementation of the regulation differs greatly from country to country," she added. "Hence, there is need for common and transparent European standards."
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