A sperm donor has passed a rare genetic disorder to at least five of the 43 babies he is thought to have fathered, after screening measures at a fertility clinic failed to detect the mutation.
The man transmitted the nerve disorder Neurofibromatosis type I (NF1), known as Von Recklinghausen’s disease.
The disease, which affects 4,000 babies a year in Britain, can cause high blood pressure, bone deformity, scoliosis, learning difficulties and eye problems, including tumours on the optic nerve.
Nordisk Cryobank, the Copenhagen clinic where the Danish man donated his sperm, refused to say whether any British babies have been affected.
However, a spokesman said the donor had fathered 43 children in ten different countries, including 18 in Sweden and Denmark.
Peter Bower, the clinic’s director general, added: ‘In the case of these five, we know the disorder came from the donor even though the disorder is not always transmitted by a person’s parents.’
He added that the clinic could not release details about where and when the babies were born because of confidentiality rules.
Its website states that all sperm is tested for illnesses including HIV and cystic fibrosis. It does not say whether it is screened for Von Recklinghausen’s disease.
Denmark is introducing new rules around sperm donation as a result of the case. From October sperm from a single donor will only be used in a maximum of 12 inseminations.
NF1 is caused by a genetic mutation. In half of all cases it is passed on from parent to child, and in the other half the mutation appears to develop on its own.
A type of cancer known as malignant peripheral nerve sheath tumours affects around 10 per cent of people with NF1.