The genomes of more than 2,000 children born with heart disorders were
analysed by a large team of researchers from Manchester, Nottingham, Oxford and
Newcastle. They found that a genetic variation near the Msx1 gene was
linked to a type of heart disease known as atrial septal defect (ASD).
Professor Bernard Keavney of Newcastle University, who led the study,
said: 'We estimated that around ten percent of ASDs may be due to the
gene we found. We can now work to find out how Msx1 and/or its neighbour
genes affect the risk of ASD'.
Congenital heart disease (CHD) is
a broad term used to describe structural faults in the heart and its major
blood vessels that are present from birth. These defects can create serious
problems as the heart struggles to pump oxygenated blood to the lungs, brain
and other tissues. ASD is a variation of CHD where a hole forms in the heart
during embryonic development, and it affects around seven out of every 1,000 people.
The genome-wide association study showed that a region on
chromosome 4 was very strongly implicated
in the development of ASD. This genomic region is near
the Msx1 gene, which is involved
in embryo formation and development.
Researchers were unable to find a
genetic marker common to all types of CHD. Although around 20 percent of diagnosed cases of CHD are due to a coexisting congenital condition, such as Down's syndrome, it is unclear whether the other 80 percent of
cases have a genetic cause.
Professor Keavney said: 'Our work
also suggests that if we conduct larger studies we will be able to find genes
that cause other types of CHD. Although we are not there yet, further studies
may enable us to give better genetic counselling to high-risk families'.
Amoils, senior research advisor at the British Heart Foundation, which part-funded the study, said: 'We still need to fund much more research like
this, to better understand the fundamental causes of congenital heart defects'.