A sperm donor passed an extremely rare and dangerous genetic ailment to five children born to four couples. The disease, severe congenital neutropenia, can be fatal in children if untreated but is so rare that sperm banks do not test for it.
The four couples used the same sperm bank. The researchers did not have any donor sperm to test but connected the children's cases to one man because they all had the same version of the defective gene and because all the couples used the same sperm bank.
Severe congenital neutropenia occurs in about one in 5 million births. Children with the disorder lack the type of white blood cell that kills bacteria, and as a result develop severe infections shortly after birth.
American Society of Reproductive Medicine guidelines require anonymous sperm donors to provide a full family medical history going back at least three generations. The guidelines say a complete chromosome screening is not required if a proper family history is taken concerning potential hereditary disorders. Sperm donors are routinely screened for more prevalent genetic disorders like cystic fibrosis, Tay-Sachs disease and sickle cell anemia, but not for rare genetic diseases.
The children are doing well through daily injections of a drug that helps build up white blood cells and fight germs and they will always have an increased risk of leukemia and a 50 percent chance of passing the disease to their own children.