Portuguese gene found
STELLENBOSCH scientists have identified a “heart disease gene” in a South African family that has been plagued by a rare heart condition for more than 300 years.
The rogue gene – which contains a rare protein mutation – has been traced back to a Portuguese emigrant who came to the Cape from Madeira in 1694. Descendants of the man – who married a woman of Dutch descent – now live throughout South Africa.
Until recently, they were far more likely than the general population to suffer fatal heart complications.
Now, however, knowledge about their genetic status means they are forewarned and able to seek help in the form of pacemakers, which allow them to live relatively normal lives.
The medical breakthrough, soon to be published in an international medical journal, is not only a major triumph for South African research but also for a father-and-son research team, professors Andries and Paul Brink, who spearheaded the project at different times during a 35-year research quest.
Brink snr, a cardiac specialist and former dean of the Stellenbosch University faculty of health sciences, first described progressive familial heart block type I, in 1977. The disease is related to problems with the heart’s electric conduction system that cause major slowing down of the heartbeat.
Now Brink jnr, together with German scientists and a senior colleague at Stellenbosch University, has pinpointed the genetic source of the problem.
Their success owes much to major advances in genetic science, in particular the mapping of the human genome, which allows scientists to compare and contrast human DNA from different communities.
By following the genealogical line of the South African “heart condition” – now found in several families that the university declined to identify in order to protect their privacy – Brink and his team were able to identify 85 living carrier descendants of the man from Madeira.
“Prior to the ’70s, people with this condition often died. That’s why it is so important to identify the individuals at risk – so that people can live normal lives,” said Brink.
Even with access to the mapped human genome, the search for the heart-attack gene involved arduous scientific work, according to Brink’s co-researcher, Professor Valerie Corfield. “There were at least 80 genes in the area where we expected to find the rogue gene. Examining all of them was a costly and time-consuming process,” she said.
The vital clue came from German scientists whose research pointed to a particular gene linked to the electrical signals of the heart.
Source http://www.timeslive.co.za/sundaytimes/article34998.ece
interesting