City slow to detect 'silent killer' gene that can cause sudden death: cardiologist
Only a handful of hospitals here offer genetic screening for people at risk of disease that causes sudden heart attacks, cardiologist says
Hong Kong has been slow to diagnose a mutated gene believed to be behind a quarter of the fatal, sudden heart attacks in middle-aged people, a senior cardiologist says.
Dr Mok Ngai-shing, consultant cardiologist at Princess Margaret Hospital, said genetic screening of the close relatives of middle-aged people who died from sudden arrhythmia death syndromes (Sads) could help detect the silent killer and minimise its fatality rate.
But the public hospital lacked the resources and training to perform such tests, he said.
"Hong Kong is still at the developing stage," said Mok. "We have fallen behind many European and Asian countries in conducting gene tests for Sads."
Only three public hospitals and a few private institutions in Hong Kong offer genetic screening for the disease. In Europe, the screening is automatically provided for first-degree relatives of Sads victims.
In the city, the cost of the gene test ranges from hundreds to thousands of dollars, depending on the type of gene tested.
"Not many personnel are trained to conduct the tests, and the resources available are also limited," said Mok. "I hope more will be done in the future."
Professor Peter Schwartz, of Italy's University of Pavia, said genetic screening had at least a 50 per cent chance of identifying a carrier of the mutated gene.
One major disease classified under Sads, the congenital Long QT syndrome, could be treated with medication and lifestyle changes once a carrier was identified, Schwartz said.
Those diagnosed as carriers of the Type 1 congenital Long QT syndrome should avoid strenuous sports and exercises as those activities might trigger a heart attack, he said.
Carriers of Type 2 of the syndrome should minimise their chances of getting shocks or hearing sudden loud noises. These included avoiding having alarm clocks or telephones in the bedroom while sleeping.
"Early intervention could reduce the risks [of the syndrome] and save lives," said Schwartz, who advised those with a history of fainting or who had family members who died of sudden heart attacks to consider taking the test.
A study conducted by Mok between 2008 and last year found that one in four Hong Kong people aged between 5 and 40 who died of sudden heart attacks might have been Sads victims.
Among the autopsies performed on 420 people who died of sudden heart attacks at three public mortuaries, 25 per cent died of an unknown cause, the study found.
"According to overseas studies, this group of young people whose deaths were unexplained could have been victims of Sads," said Mok.
A new local NGO, the Sads Hong Kong Foundation, said it would conduct a study into the disease by obtaining the bodies of 40 young people who died suddenly for molecular autopsies, and by recruiting 160 first-degree relatives of such victims for clinical evaluation.