Virus Weaves Itself into the DNA Transferred from Parents to Babies

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> Virus Weaves Itself into the DNA Transferred from Parents to Babies

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> Effects of unique form of congenital infection unknown

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> 9/2/2008

> University of Rochester Medical Center

> http://news.biocompare.com/newsstory.asp?id=242354

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> Parents expect to pass on their eye or hair color, their knobby knees

> or their big feet to their children through their genes. But they

> don't expect to pass on viruses through those same genes.

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> New research from the University of Rochester Medical Center shows

> that some parents pass on the human herpes virus 6 (HHV-6) to their

> children because it is integrated into their chromosomes. This is the

> first time a virus has been shown to become part of the human DNA and

> then get passed to subsequent generations. This unique mode of

> congenital infection may be occurring in as many as 1 of every 116

> newborns, and the long-term consequences for a child's development

> and immune system are unknown.

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> " At this point, we know very little about the implications of this

> type of infection, but the section of the chromosome into which the

> virus appears to integrate is important to the maintenance of normal

> immune function, " said Caroline Breese Hall, M.D., professor of

> Pediatrics and Medicine at the University of Rochester Medical

> Center, and author of the study which publishes in Pediatrics this

> month. " With further study, we hope to discern whether this type of

> infection affects children differently than children infected after

> birth. "

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> HHV-6 causes roseola, an infection that is nearly universal by 3

> years of age. The typical roseola syndrome produces several days and

> up to a week of a high fever and may have variable other symptoms

> including mild respiratory and gastrointestinal symptoms. With

> roseola, just as the fever breaks, the child may briefly develop a

> rash. A congenital infection of HHV-6 – or one that is present at

> birth – produces high levels of virus in the body but scientists

> (doctors) do not know whether it produces any developmental or immune

> system problems.

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> Some congenital infections can cause serious problems in fetuses. If

> a mother contracts cytomegalovirus (CMV) while pregnant, her fetus is

> at risk of hearing or vision loss, developmental disabilities and

> problems with the lungs, liver and spleen. Some of those health

> problems don't show up until months or years after birth. HHV-6 virus

> is a closely related virus to CMV, and the congenital infection rate

> of CMV is similar to that of congenital HHV-6 – about 1 percent.

> However, this research shows that a congenital HHV-6 infection

> differs greatly from a congenital CMV infection in that it is often

> integrated into the chromosomes of the baby rather than passed

> through the placenta.

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> " This is the first time a herpes virus has been recognized to

> integrate into the human genome. To think that it's actually a part

> of us – that's really fascinating, " said Caserta, M.D.,

> associate professor of Pediatrics at the University of Rochester

> Medical Center and one of the paper's authors. " This opens up a whole

> new realm of exploration. "

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> Of 254 children enrolled in this study between July 2003 and April

> 2007, 43 had congenital HHV-6 infections based on cord blood samples.

> Of 211 children without congenital infection, 42 were children who

> acquired an HHV-6 infection during the study. Of the infants who had

> congenital infections, 86 percent of them (37) had the virus

> integrated into their chromosomes. Only six of the congenitally

> infected babies were infected by the mother through the placenta .

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> Children who had integrated HHV-6 had higher levels of virus in the

> body than those who were infected through the placenta. HHV-6 DNA was

> found in the hair of one parent of all children with integrated virus

> with available parental samples (18 mothers and 11 fathers), which

> means the children acquired the integrated infections through their

> mother's egg or father's sperm at conception. The virus's DNA was not

> found in hair samples of parents of children who were infected after

> birth.

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> ###

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> This study is part of a series of ongoing studies on children with

> HHV-6 infections at the University's Golisano Children's Hospital at

> Strong. This study was funded by grants from the National Institute

> of Child Health and Development and, in part, by grants from the

> General Clinical Research Center, the National Center for Research

> Resources, the National Institutes of Health and the HHV-6 Foundation.

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