Link: http://www.nytimes.com/2006/05/19/healt ... ref=slogin
Just a few random thoughts:Sperm Donor Seen as Source of Disease in 5 Children
By DENISE GRADY
Published: May 19, 2006
A sperm donor in Michigan passed a rare and serious genetic disease to five children born to four couples, doctors are reporting today.
The doctor who discovered the cases said that all four couples were clients of the same sperm bank. That bank, the doctor added, assured him that it had discarded its remaining samples from the man and had told him he could no longer be a donor.
It is not known how many children the donor had fathered, whether he knew he carried the disease before he donated sperm, or whether the bank had informed him of his condition after learning about it. The doctor declined to name the sperm bank.
A report on the cases is being published today in The Journal of Pediatrics.
An expert in genetics and reproductive medicine who is not associated with the report, Dr. Joe Leigh Simpson at the Baylor College of Medicine, said that sperm donors are routinely tested for most common genetic diseases, like cystic fibrosis and sickle cell anemia, but not for extremely rare ones like severe congenital neutropenia, the one afflicting the Michigan children.
Children with the disease lack a type of white blood cell called a neutrophil, according to the doctor who discovered the cases, Dr. Lawrence A. Boxer, the director of pediatric hematology and oncology at the University of Michigan, and an author of the report. As a result, the children are highly vulnerable to infections and prone to leukemia.
Without treatment, many die in childhood. But daily shots of a drug called Neupogen can help them make the missing cells and fight off infections. It does not ward off leukemia, though. The drug costs $200 a day, but, Dr. Boxer said, many get it free as part of a study.
"The kids are doing terrific," Dr. Boxer said. "They're all leading healthy lives." But, he added, they have a 50 percent chance of passing the gene and the disease to their own children.
The disease is rare; since Dr. Boxer is an expert on it, families find their way to him, he said. It affects only about one in five million children, and when he encountered three affected families in one year, "it became pretty striking," he said. Then, a fourth family appeared. The families had three sets of twins and one other child from the donor; all told, five children were affected — the single child, one pair of twins and one twin each from the two other sets.
"The mothers, when initially they brought the children to me, volunteered without my asking how they conceived the kids," Dr. Boxer said. To protect the privacy of his patients Dr. Boxer has not revealed their identities, not even to one another.
He asked where they had obtained the sperm, and if they had cards from the sperm bank that would allow tracing of the donor. All produced cards with the same donor number.
Genetic testing showed that all the affected children had the exact same version of the defective gene — and that none of their mothers did. The donor was the only explanation.
Dr. Boxer called the sperm bank and requested one of the donor's samples for testing but, he said, the sperm bank refused, saying the donor had given permission for the sperm to be used only for conception, not genetic testing. Nor would the bank contact the donor to ask for his cooperation, Dr. Boxer said.
"They were fearful, I'm sure, of litigation, though nobody spoke about that," Dr. Boxer said. "The less that was unraveled here the better off they were going to be."
Dr. Boxer said that while he had no information about the donor, he and his colleagues suspected that the man had an unusual condition, mosaicism, in which the mutant gene occurred only in his sperm and not in the rest of his body.
Otherwise, Dr. Boxer said, the donor would have been extremely ill. The sperm bank said he had been healthy. If he did have mosaicism, he would have had no symptoms and there would have been no reason to test him.
Dr. Simpson of Baylor University said he had not heard of a case like this before, but added: "It's not surprising. You have the same risks in sperm donors as when children are naturally conceived. It's not unique to the sperm donor situation."
This is an illustration of why it's not a good thing to have one sperm donor be the biological father of too many children - genetic disease is not always apparent. Not to mention every mutation has a point of origin.
Genetic mosaicism used to be in the realm of "theory - but we have no examples". Then it became "very, very rare". Now, with genetic sequencing being easier/cheaper and genetic testing more common, while it's still rare, it's apparently NOT as rare as people used to think it was.
If the donor is not a genetic mosaic, it may simply be that a mutation has occured in his sperm-generating cells, which may well explain his not being affected.
What do you think of the ethical issues involved in either violating the donor's anonymity so other possible suffers can be located vs. keeping him anonymous and possibly missing a correct diagnosis in a child suffering from an easily fatal disease?