A savior baby or savior sibling is a child who is conceived in order to provide a stem cell transplant to a sibling that is affected with a fatal disease, such as

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

Fanconi anemia Fanconi anaemia (FA) is a rare genetic disease resulting in impaired response to DNA damage. Although it is a very rare disorder, study of this and other bone marrow failure syndromes has improved scientific understanding of the mechanisms of no ...

, that can best be treated by

hematopoietic stem cell transplantation Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood in order to replicate inside of a patient and to produce ...

. The savior sibling is conceived through

in vitro fertilization In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) f ...

. Fertilized

zygotes A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellula ...

are tested for genetic compatibility (

human leukocyte antigen The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for the regulation of the immune system. The HLA system is also known as the human version of th ...

(HLA) typing), using

preimplantation genetic diagnosis Preimplantation genetic diagnosis (PGD or PIGD) is the genetic profiling of embryos prior to implantation (as a form of embryo profiling), and sometimes even of oocytes prior to fertilization. PGD is considered in a similar fashion to prenatal ...

(PGD), and only zygotes that are compatible with the existing child are implanted. Zygotes are also tested to make sure they are free of the original genetic disease. The procedure is controversial.

Indications

A ''savior sibling'' may be the solution for any disease treated by hematopoietic stem cell transplantation. It is effective against genetically detectable (mostly monogenic) diseases, e.g.

Diamond–Blackfan anemia Diamond–Blackfan anemia (DBA) is a congenital erythroid aplasia that usually presents in infancy. DBA causes low red blood cell counts (anemia), without substantially affecting the other blood components (the platelets and the white blood cel ...

and

β-thalassemia Beta thalassemias (β thalassemias) are a group of inherited blood disorders. They are forms of thalassemia caused by reduced or absent synthesis of the beta chains of hemoglobin that result in variable outcomes ranging from severe anemia to cli ...

, in the ailing sibling, since the savior sibling can be selected to not have inherited the disease. The procedure may also be used in children with leukemia, and in such cases HLA match is the only requirement, and not exclusion of any other obvious genetic disorder.

Procedure

Multiple embryos are created and

is used to detect and select ones that are free of a

genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...

and that are also a HLA match for an existing sibling who requires a transplant. Upon birth, umbilical

cord blood Cord blood (umbilical cord blood) is blood that remains in the placenta and in the attached umbilical cord after childbirth. Cord blood is collected because it contains stem cells, which can be used to treat hematopoietic and genetic disorders s ...

is taken and used for

Laws

* In the United Kingdom, the

Human Fertilisation and Embryology Authority The Human Fertilisation and Embryology Authority (HFEA) is an executive non-departmental public body of the Department of Health and Social Care in the United Kingdom. It is a statutory body that regulates and inspects all clinics in the United ...

(HFEA) has ruled that it is lawful to use modern reproductive techniques to create a savior sibling. *In

Victoria, Australia Victoria is a state in southeastern Australia. It is the second-smallest state with a land area of , the second most populated state (after New South Wales) with a population of over 6.5 million, and the most densely populated state in ...

, use of PGD for HLA typing is reviewed by the

Infertility Treatment Authority Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal stat ...

on a case-by-case basis.

Ethical considerations

Arguments for or against the use of PGD/HLA tissue typing are based on several key issues including the commodification and welfare of the donor child. The main ethical argument against is the possible exploitation of the child, e.g. potential adverse psychological effects on a child born not for itself but to save another, and the possible future emotional reaction of the savior sibling upon discovering that they were born solely to save the life of the recipient, rather than being 'wanted' for reasons other than transplantation. A survey of 4,000 Americans showed that 61% approved of PGD use for savior siblings.Genetic testing of embryos to pick 'savior sibling' OK with most Americans
medicalnewstoday.com, Article Date: 4 May 2004 – 0:00 PDT

History

Yury Verlinsky and collaborators described the first case in 2001."Preimplantation Diagnosis for Fanconi Anemia Combined With HLA Matching"
Yury Verlinsky et al. ''The Journal of the American Medical Association''.

Popular culture

The novel '' My Sister's Keeper'', later adapted into a film, is about a child who was born as a savior sibling to her sister Kate who is affected by acute promyelocytic leukemia. In the British soap opera ''

Emmerdale ''Emmerdale'' (known as ''Emmerdale Farm'' until 1989) is a British soap opera that is broadcast on ITV1. The show is set in Emmerdale (known as Beckindale until 1994), a fictional village in the Yorkshire Dales. Created by Kevin Laffan, ...

'',

Debbie Dingle Debbie Dingle (also Jones and Barton) is a fictional character from the British ITV soap opera ''Emmerdale'', played by Charley Webb. Webb has taken maternity leave three times, with the first time being in 2010 and the second throughout 201 ...

gave birth to her son Jack, who would serve as a savior sibling to his older sister Sarah, who was suffering from

. On the popular American show ''

CSI: Crime Scene Investigation ''CSI: Crime Scene Investigation'', also referred to as ''CSI'' and ''CSI: Las Vegas'', is an American procedural forensics crime drama television series that ran on CBS from October 6, 2000, to September 27, 2015, spanning 15 seasons. This wa ...

'', the episode "Harvest" deals with the reported abduction and later murder of a thirteen-year-old girl named Alycia who was later revealed to be a savior sibling for her brother Daniel. In the American show ''

Heroes Heroes or Héroes may refer to: * Hero, one who displays courage and self-sacrifice for the greater good Film * ''Heroes'' (1977 film), an American drama * ''Heroes'' (2008 film), an Indian Hindi film Gaming * ''Heroes of Might and Magic'' ...

'', one of the protagonists, Mohinder Suresh, is revealed to have been conceived to cure his sister Shanti of a deadly disease known as the Shanti Virus, although he was ultimately born too late to save her life. His antibodies act as a cure for other patients with the disease throughout the show as well. On ''

Star Trek: Enterprise ''Star Trek: Enterprise'', titled simply ''Enterprise'' for its first two seasons, is an American science fiction television series created by Rick Berman and Brannon Braga. It originally aired from September 26, 2001, to May 13, 2005 on Uni ...

'', the episode " Similitude" sees a clone created of

Trip Tucker Charles "Trip" Tucker III, portrayed by Connor Trinneer, is a fictional character in the television series ''Star Trek: Enterprise''. Tucker was the chief engineer on the ''Enterprise'' and also briefly served in the same role aboard the Ente ...

for the purpose of organ harvesting. "Sim" is born through the highly controversial use of an alien lifeform. The novel '' Never Let Me Go'', later adapted into a film, is centred around a dystopian future society where human clones are created and allowed to live to their teenage years before being used for organ harvesting. The film '' Parts: The Clonus Horror'' has a similar premise. In the ''

Grey's Anatomy ''Grey's Anatomy'' is an American medical drama television series that premiered on March 27, 2005, on ABC as a mid-season replacement. The series focuses on the lives of surgical interns, residents, and attendings as they develop into s ...

'' episode "I Bet It Stung," the character Donna is a savior sibling to her older sister Reese. In the '' 9-1-1'' episode "Buck Begins", it is revealed that Evan "Buck" Buckley was conceived as a savior sibling for his older brother Daniel. In the Korean Drama 'The Penthouse', the character Anna is adopted by a Korean-American family to be a savior sibling to their son, Logan Lee, who was suffering from bone marrow cancer at the time.

References

External links

"Made to Order Savior"
''New York Times Magazine''
£Select a Baby’s Health, Not Eye Color"
''Los Angeles Times'' Op-ed {{DEFAULTSORT:Savior Sibling Ethically disputed medical practices Medical genetics Sibling