Baby will donate cells to treat brother with rare genetic syndrome

Shwachman-Diamond Syndrome is a rare genetic disorder that occurs in about one in 50,000 births.

By JUDY SIEGEL-ITZKOVICH
For the first time in Israel, a healthy baby girl has been born at Jerusalem's Shaare Zedek Medical Center to a couple who both carry single defective genes that can give their offspring Shwachman-Diamond Syndrome, a rare genetic disorder that occurs in about one in 50,000 births. Not only is the baby - who in her embryonic stage was selected from among other embryos that carried the disease - healthy, but she will be able to donate bone marrow to her older brother, who suffers from the syndrome. The parents and relatives were not found suitable to donate bone marrow to their sick son. But they decided that they wanted to have more children - healthy ones - by undergoing preimplantation genetic diagnosis (PGD). This involves taking a cell from embryos a few days old to examine the genes and implant healthy embryos in the woman's womb. The couple are in their 20s. Their son was diagnosed at nine months of age with the syndrome, which is a rare genetic condition. Shwachman-Diamond Syndrome (SDS) is a genetic disorder that occurs in approximately one in 50,000 births and involves bone marrow problems causing inadequate white cells in the blood, pancreatic defects leading to digesting difficulties, skeletal abnormalities and short stature. Patients are also at risk for sometimes fatal complications such as severe infections, acute myelogenous leukemia and bone marrow failure. This condition is inherited in an autosomal recessive pattern, in which both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. PGD, a very complicated process, is used to rule out disease and to identify embryos that eventually can safely donate bone marrow to a sibling. Until now, there have been no reports on the birth of any child suitable to donate bone marrow to a sibling who needs a donation. Couples who wanted to undergo such a process had to go abroad to one of the few centers that perform it, but have had few successes. Dr. Geona Alterescu (head of Shaare Zedek's PGD center), Prof. Ephrat Levy-Lahad (director of the medical genetics unit) and Prof. Ehud Margaliot (head of its in-vitro fertilization unit) successfully carried out the procedure. A few days ago, a healthy baby who is free of the syndrome was born, and her bone marrow was shown to be absolutely compatible with her brother's.