Survivor Siblings

One of the most important hopes of any parent is to raise a happy and healthy child, and watch that child grow up and become an adult. What if one of those children had a disease that would one day claim his or her life? What if there was an option that could save your child’s life? To what lengths will parents go to save the life of a terminally ill child? A savior sibling is a child selected as a result of genetic screening to have some innate characteristics that will help save the life of an existing brother or sister (Saviour sibling).

In 1990, Abe and Mary Ayala became the first successful publicized case in which a family sought to conceive a child (Marissa) to save another child (Anissa). Anissa was battling leukemia when her parents decided to conceive another child that was an exact bone marrow match. They gave birth to a healthy baby girl they named Marissa who at 14 months of age donated bone marrow that saved her sister’s life. Preimplantation Genetic Diagnosis or PGD tests a woman’s embryos outside of her body for genetic sequence that are linked to a variety of conditions.

PGD was developed for couples at risk for passing on a serious genetic mutation. Since 1999 it has been most widely used to prevent the birth of children with conditions such as Down syndrome, Tay-Sachs disease, cystic fibrosis, sickle cell, Huntington’s chorea, and Cooley’s anemia. However, PGD is increasingly being used for other reasons. These include social sex selection, creating “savior siblings” who can provide bone marrow and other transplant tissues to sick older siblings, and selecting against embryos with genes correlated with late-onset and non-fatal conditions.

Some clinics have even offered the technique for purely cosmetic traits including eye color, hair color, and skin complexion (geneticsandsociety. org). It also contributes to concerns over the creation of what are critically called designer babies, though the latter is a broad term for children created to any sort of parental specifications or for purely cosmetic traits such as eye color, hair color and skin complexion. Savior siblings are specifically created to help an existing child (worldwidewords. org).

Savior siblings are often conceived to serve as a bone marrow and umbilical cord blood stem cell donor for an ill older sibling. PGD is preformed early to ensure that the embryo is an identical Human Leukocyte Antigen (HLA) match. Additionally, the embryo is screened for traits of the same inherited condition. About 70% or 7 out of 10 individuals who need a transplant do not have a suitable donor in their immediate family. A sibling with an exact HLA match is important because it increases the likelihood of a successful transplant (bethematch. org).

A major advantage of umbilical cord blood is that HLA-matching is less critical, because the lymphocytes in the cord blood are less immunologically reactive than those of older donors (American Academy of Pediatrics). When the siblings are HLA-identical there is less of a chance of Graft Versus Host Disease (GVHD) when using umbilical cord blood. Savior siblings may be a solution for any disease that is treated with hematopoietic stem cell transplantation. It is effective in treating conditions such as Fanconi anemia, Dimond-Blackfin anemia, and thalassemia in an ill sibling.

This procedure may also be useful in treating children leukemia. Upon birth the umbilical cord blood is collected and stored. The number of umbilical cord stem cells that can be obtained may not be adequate, and decisions need to be made about collecting additional hematopoietic stem cells from the donating child at a later date (American Academy of Pediatrics). As in the case of Marissa Ayala, her cord blood was stored for more than a year when additional stem cells were collected from her by needle aspiration from her bone marrow.

This was done to ensure an adequate number of cells to transplant to her sister Anissa. Sibling donors may receive G-CSF which stimulates their bone marrow to create more stem cells, to make sure that there is an adequate number of cells for transplant. The recipient is put through treatment that destroys his or her bone marrow cells, and the stem cells from the umbilical cord blood and bone marrow are transplanted. There are specific conditions under which a child is able to participate as a hematopoietic stem cell donor. There are five criteria that must be fulfilled for a child to be a donor.

The criteria are: (1) there is no healthy suitable adult relative that qualifies to be a donor; (2) there is a strong positive relationship between the donor and the recipient; (3) there is a likelihood that the recipient will benefit from the transplant; (4) the clinical, emotional, and psychosocial risks of the donor are minimized; (5) parental permission and the assent of the donating child are obtained. For the first criteria the family is urged to screen adult family member as well as children in the initial screening. In a case where there is more than one sibling that is a

match the sibling that is closest to consenting age should be asked about donating. In the second criteria, a strong positive personal relationship between donor and recipient increases the likelihood that the donor will experience a psychosocial benefit. In the third criteria, it is hard to predict the success of the transplant. It depends on the procurement of the donor stem cells and the prognosis of the recipient. In the fourth criteria, it is up to the physician and transplant staff to ensure that the parents consider the risks and benefits to both the recipient and the donor.

Donor children can be prepared by role play so that they understand their role and what is expected. Children should be allowed to ask questions about the procedure and allowed to take part in the decision making to the extent of their ability. In the last criteria parental permission and donor assent are obtained. It is also recommended that donors have a donor advocate whose purpose is to help the donor and the parents understand the process and procedures. The donor advocate also protects the well-being of the donor.

What is the ethical consideration of using children as hematopoietic stem cell donors? The risks to the minors who serve as stem cell donors can be characterized as more than minimal (American Academy of Pediatrics). The most common risk is that of the anesthesia before any procedure. Some of the short-term effects associated with bone marrow donation are fatigue, pain at the donation site, lower back pain, headaches, trouble walking, sleeping issues and less common bleeding issues.

In rare cases the donor may experience chronic pain at the donation site. Others may question the psychosocial effects on the donor child. Some data show that many children experience some distress related to their role as donor. Some children may feel neglected by the parents post transplant when one or both parents spend a significant amount of time at the hospital, but these feelings also affect nondonor siblings. This feeling of neglect and loneliness is normal for those children who have an ill sibling who is the main focus of the parents.

Nondonors, however, felt some envy toward donors who could contribute to the care of an ill sibling. Donor siblings may also experience some guilt if the transplant is unsuccessful. Children that are donating stem cells should be aware that the outcome of the procedure is out of their control. The family of both the donor and the recipient should be supportive and attentive to the needs of both children. There are other ethical concerns that are focused around the IVF procedure. This is where multiple embryos are fertilized and only one is selected for implantation.

The embryos are screened for genetic defects, and they are also screened for an HLA match. Those embryos that are not a match are discarded or used for research. Some people believe that to destroy the embryos is cutting a life short that has already begun. Gene selection is a controversial subject due to the concept of “designer babies. ” This is conceiving a child merely for superior genetic characteristics. There is also controversy about the way these babies are conceived. It is argued that the procedure ends human lives, by discarding fertilized embryos.

Savior siblings save the life of an older sibling. Children that are conceived to save siblings are not only loved for their role in saving their sibling’s life, but also as another member of the family. There is a dream that every parent has to see his or her children grow up to be healthy and happy adults. For some families, this is not a possibility when their child is terminally ill. Now, with new technology it is possible to save the life of that child and have another child to love.