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Rare debilitating condition doesn't stop these brothers
Fitness enthusiasts still keep active despite disease that affects mobility
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Calvin Yang
Six years ago, brothers Kenneth and Eugene Tan - who have completed countless marathons and adventure races between them - could easily finish a 2.4km run in under 10 minutes.
Now, former naval diving officer Kenneth Tan, 30, and Mr Eugene Tan, 28, who was a commando during his national service, are unable to walk long distances without help.
