Virus weaves itself into the DNA transferred from parents to babies

Sep 02, 2008

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.

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.

"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."

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.

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.

"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 Mary 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."

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 .

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.

Source: University of Rochester

Explore further: Researchers find unsuspected characteristics of new CF drugs, offering potential paths to more effective therapies

add to favorites email to friend print save as pdf

Related Stories

Social Security spent $300M on 'IT boondoggle'

6 hours ago

(AP)—Six years ago the Social Security Administration embarked on an aggressive plan to replace outdated computer systems overwhelmed by a growing flood of disability claims.

Cheaper wireless plans cut into AT&T 2Q profit

6 hours ago

(AP)—AT&T posted lower net income for the latest quarter due to cheaper cellphone plans it introduced as a response to aggressive pricing from smaller competitor T-Mobile US.

Awarded a Pell Grant? Better double-check

6 hours ago

(AP)—Potentially tens of thousands of students awarded a Pell Grant or other need-based federal aid for the coming school year could find it taken away because of a mistake in filling out the form.

Recommended for you

Strategy proposed for preventing diseases of aging

17 hours ago

Medicine focuses almost entirely on fighting chronic diseases in a piecemeal fashion as symptoms develop. Instead, more efforts should be directed to promoting interventions that have the potential to prevent ...

User comments : 0