Punggol East MP and Deputy Speaker of Parliament Charles Chong disclosed yesterday that he went for a liver transplant earlier this month, with his younger son as the donor.
The People's Action Party had earlier announced that the veteran MP was taking eight weeks of medical leave following a "planned medical procedure".
In an e-mail interview with The Straits Times, Mr Chong, 63, said he was diagnosed with non-alcoholic steatohepatitis three years ago after a routine medical check-up.
He said the condition - liver inflammation caused by a build-up of fat - is "not something which has had any impact on my work or personal life". But he added that it could lead to liver cirrhosis, where the liver is permanently damaged and no longer able to work properly.
His doctors gave him the green light to continue with his political and grassroots duties as he was still in good physical condition, he said.
What is non-alcoholic steatohepatitis?
Non-alcoholic steatohepatitis (Nash) is an inflammation of the liver, which happens when fat builds up in that organ.
Nash is the most serious form of non-alcoholic fatty liver disease. Its most common causes are obesity, diabetes and genetic factors, instead of heavy drinking.
Patients may experience no symptoms for years until the condition becomes more advanced, although some patients may not get worse.
But in the long run, scar tissue can build up in the liver over time.
This can result in cirrhosis, where the liver hardens so much that it is permanently damaged and cannot function properly.
About 25 per cent to 30 per cent of patients with Nash develop liver cirrhosis, with older people and diabetics at higher risk.
Liver cirrhosis can lead to complications such as liver cancer, liver failure or both.
While monitoring his condition, doctors found several small lesions on his liver. He said that although there was no immediate need for surgery as his liver was still functioning well, they advised him in October this year that a liver transplant would be best in the long term.
"We decided to do it now while I am still in good health overall, rather than wait until things got worse," he said.
Mr Chong said both his sons volunteered to be donors, but his younger son Glenn, a 30-year-old regional programme manager at think-tank Konrad-Adenauer-Stiftung, was a better match.
The surgery took place on Dec 1 at the National University Hospital. Both father and son were discharged two weeks later, on Dec 14.
A seven-term MP who entered politics in 1988, Mr Chong wrested the Punggol East seat back from the Workers' Party at last year's general election after he defeated incumbent Lee Li Lian.
His doctors have told him to get plenty of rest, and he is taking immunosuppressants so that his body does not reject the new liver.
The medication has resulted in his body having a lower immunity than usual, but he is taking the opportunity to eat more healthily - "less oil, less salt in my diet", he said.
He will also have to spend the festive period doing follow-up blood and liver function tests, which he does not mind "as that takes the monotony out of being at home all the time".
He is also "itching to get back to Punggol East", but can do so only after doctors give him the all-clear.
"If things go well, my doctors may clear me for limited public engagements after (the eight weeks of medical leave is over), but it is still too early to say right now," he said.
In his absence, his activists, grassroots leaders and MPs from Pasir Ris-Punggol GRC have been helping to look after his single-member constituency.
Mr Chong singled out Deputy Prime Minister Teo Chee Hean for special thanks, for attending the Punggol East Meet-the-People Session on Monday as well as other community events in the ward in the past few weeks.
In a Facebook post last night, he also thanked all his well-wishers. "My family and I are very touched by the concern and words of encouragement I have received since I had my surgery," he wrote.
Minister of State for Manpower and Pasir Ris-Punggol GRC MP Teo Ser Luck said he had been exchanging WhatsApp messages with Mr Chong, whose text messages displayed his "trademark good humour". He said: "Charles is like that - he will handle any difficult situation well."
Asked about his current condition, Mr Chong said he feels "pretty good, maybe a little less energy than before, but the initial pain from the surgery is pretty much gone now".
"I hope to provide Ser Luck and the rest of my colleagues in Pasir Ris-Punggol with many more entertaining text messages," he said.