IN QUESTION Abnormal gene expression may be tied to in vitro techniques.
Picture Emerging on Genetic Risks of IVF
IN QUESTION Abnormal gene expression may be tied to in vitro techniques.
By GINA KOLATA
Published: February 16, 2009
Over the past 30 years, in vitro fertilization has been reassuringly safe. Millions of healthy children have been born and developed normally. And the first IVF baby, Louise Brown, born in England on July 25, 1978, now has her own child, 2-year-old Cameron, conceived without the technique.
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Related
Health Guide: In Vitro Fertilization IVF
But researchers have always wondered whether there might be subtle changes in an embryo that is grown for several days in a petri dish, as IVF embryos are — and, if so, whether would there be any consequences.
Now, with new epidemiological studies and new techniques that allow scientists to probe the genes of embryo cells, some tentative answers are starting to emerge.
The issues have nothing to do with the chances that a woman will have twins, triplets or even, as just happened in California, octuplets. Instead, they involve questions of whether there are changes in gene expression or in developmental patterns, which may or may not be obvious at birth.
For example, some studies indicate that there may be some abnormal patterns of gene expression associated with IVF and a possible increase in rare but devastating genetic disorders that appear to be directly linked to those unusual gene expression patterns. There also appears to be an increased risk of premature birth and of babies with low birth weight for their gestational age.
In November, the Centers for Disease Control and Prevention published a paper reporting that babies conceived with IVF, or with a technique in which sperm are injected directly into eggs, have a slightly increased risk of several birth defects, including a hole between the two chambers of the heart, a cleft lip or palate, an improperly developed esophagus and a malformed rectum. The study involved 9,584 babies with birth defects and 4,792 babies without. Among the mothers of babies without birth defects, 1.1 percent had used IVF or related methods, compared with 2.4 percent of mothers of babies with birth defects.
The findings are considered preliminary, and researchers say they believe IVF does not carry excessive risks. There is a 3 percent chance that any given baby will have a birth defect.
But the real question — what is the chance that an IVF baby will have a birth defect? — has not been definitively answered. That would require a large, rigorous study that followed these babies. The C.D.C. study provides comparative risks but not absolute risks.
Yet even though the risks appear to be small, researchers who are studying the molecular biology of embryos grown in petri dishes say they would like a better understanding of what happens, so they can improve the procedure and allow couples to make more informed decisions.
“There is a growing consensus in the clinical community that there are risks,” said Richard M. Schultz, associate dean for the natural sciences at the University of Pennsylvania. “It is now incumbent on us to figure out what are the risks and whether we can do things to minimize the risks.”
And although the questions are well known, the discussion has been largely confined to scientists, said Dr. Elizabeth Ginsburg, president of the Society for Assisted Reproductive Technology.
Dr. Ginsburg, who is the medical director of in vitro fertilization at Brigham and Women’s Hospital in Boston, says her center’s consent forms mention that there might be an increased risk for certain rare genetic disorders. But, she says, none of her patients have been dissuaded.
Richard G. Rawlins, who directs the in vitro fertilization and assisted reproduction laboratories at the Rush Centers for Advanced Reproductive Care in Chicago, said that when he spoke to patients he never heard questions about growing embryos in the laboratory and the possible consequences.
“I have never had a patient ask me anything” about it, he said, adding, “For that matter, not many doctors have ever asked, either.”
Dr. Andrew Feinberg, a professor of medicine and genetics at Johns Hopkins, became concerned about the lack of information about IVF eight years ago when he and a colleague, Dr. Michael R. DeBaun, were studying changes in gene expression that can lead to cancer.
Their focus was on children with Beckwith-Wiedemann syndrome, characterized by a 15 percent risk of childhood cancers of the kidney, liver or muscle; an overgrowth of cells in the kidney and other tissues; and other possible abnormalities, among them a large tongue, abdominal-wall defects and low levels of blood sugar in infancy.
The syndrome, Dr. Feinberg and Dr. DeBaun found, was often caused by changes in the expression of a cluster of genes, and those changes also are found in colon and lung cancers. Children with those gene alterations had a 50 percent risk of the childhood cancers. The normal risk is less than 1 in 10,000.
The two investigators recruited children with the disorder, following them and studying them in their clinic. Then, several mothers in the study who had had IVF asked the researchers: Was it possible that the fertility treatments had caused Beckwith-Wiedemann syndrome?
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IN QUESTION Abnormal gene expression may be tied to in vitro techniques.
By GINA KOLATA
Published: February 16, 2009
Over the past 30 years, in vitro fertilization has been reassuringly safe. Millions of healthy children have been born and developed normally. And the first IVF baby, Louise Brown, born in England on July 25, 1978, now has her own child, 2-year-old Cameron, conceived without the technique.
Skip to next paragraph
Related
Health Guide: In Vitro Fertilization IVF
But researchers have always wondered whether there might be subtle changes in an embryo that is grown for several days in a petri dish, as IVF embryos are — and, if so, whether would there be any consequences.
Now, with new epidemiological studies and new techniques that allow scientists to probe the genes of embryo cells, some tentative answers are starting to emerge.
The issues have nothing to do with the chances that a woman will have twins, triplets or even, as just happened in California, octuplets. Instead, they involve questions of whether there are changes in gene expression or in developmental patterns, which may or may not be obvious at birth.
For example, some studies indicate that there may be some abnormal patterns of gene expression associated with IVF and a possible increase in rare but devastating genetic disorders that appear to be directly linked to those unusual gene expression patterns. There also appears to be an increased risk of premature birth and of babies with low birth weight for their gestational age.
In November, the Centers for Disease Control and Prevention published a paper reporting that babies conceived with IVF, or with a technique in which sperm are injected directly into eggs, have a slightly increased risk of several birth defects, including a hole between the two chambers of the heart, a cleft lip or palate, an improperly developed esophagus and a malformed rectum. The study involved 9,584 babies with birth defects and 4,792 babies without. Among the mothers of babies without birth defects, 1.1 percent had used IVF or related methods, compared with 2.4 percent of mothers of babies with birth defects.
The findings are considered preliminary, and researchers say they believe IVF does not carry excessive risks. There is a 3 percent chance that any given baby will have a birth defect.
But the real question — what is the chance that an IVF baby will have a birth defect? — has not been definitively answered. That would require a large, rigorous study that followed these babies. The C.D.C. study provides comparative risks but not absolute risks.
Yet even though the risks appear to be small, researchers who are studying the molecular biology of embryos grown in petri dishes say they would like a better understanding of what happens, so they can improve the procedure and allow couples to make more informed decisions.
“There is a growing consensus in the clinical community that there are risks,” said Richard M. Schultz, associate dean for the natural sciences at the University of Pennsylvania. “It is now incumbent on us to figure out what are the risks and whether we can do things to minimize the risks.”
And although the questions are well known, the discussion has been largely confined to scientists, said Dr. Elizabeth Ginsburg, president of the Society for Assisted Reproductive Technology.
Dr. Ginsburg, who is the medical director of in vitro fertilization at Brigham and Women’s Hospital in Boston, says her center’s consent forms mention that there might be an increased risk for certain rare genetic disorders. But, she says, none of her patients have been dissuaded.
Richard G. Rawlins, who directs the in vitro fertilization and assisted reproduction laboratories at the Rush Centers for Advanced Reproductive Care in Chicago, said that when he spoke to patients he never heard questions about growing embryos in the laboratory and the possible consequences.
“I have never had a patient ask me anything” about it, he said, adding, “For that matter, not many doctors have ever asked, either.”
Dr. Andrew Feinberg, a professor of medicine and genetics at Johns Hopkins, became concerned about the lack of information about IVF eight years ago when he and a colleague, Dr. Michael R. DeBaun, were studying changes in gene expression that can lead to cancer.
Their focus was on children with Beckwith-Wiedemann syndrome, characterized by a 15 percent risk of childhood cancers of the kidney, liver or muscle; an overgrowth of cells in the kidney and other tissues; and other possible abnormalities, among them a large tongue, abdominal-wall defects and low levels of blood sugar in infancy.
The syndrome, Dr. Feinberg and Dr. DeBaun found, was often caused by changes in the expression of a cluster of genes, and those changes also are found in colon and lung cancers. Children with those gene alterations had a 50 percent risk of the childhood cancers. The normal risk is less than 1 in 10,000.
The two investigators recruited children with the disorder, following them and studying them in their clinic. Then, several mothers in the study who had had IVF asked the researchers: Was it possible that the fertility treatments had caused Beckwith-Wiedemann syndrome?
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