A leading Irish politician has been diagnosed with Lou Gehrig's disease, the crippling motor neuron disease that is usually fatal.

Michael Fitzpatrick, a leading Fianna Fail parliamentary member from Kildare, was given the diagnoses three weeks ago but has vowed to fight it. 

"I have been diagnosed with Motor Neuron Disease," he told the Sunday Independent. "The final tests were done one day and I was told the next. It is, of course, a progressive disease and I am on two tablets a day, which I am told, will slow down progression of it. I'm happy with that. I don't feel any worse than I did at Christmas. The power in my right arm is diminished substantially, apart from that I feel OK.

"I am a public representative and it's my duty to let the people know that there is something wrong but that I am available to them, to do all the work I've been doing. I will do that for as long as I can," he said in the Sunday Independent interview.

"The first symptoms appeared last November. I noticed that there was something wrong with my right hand, with the power I had. I went to the doctor in December and he sent me into the Hermitage in Lucan on January 4 where I had X-rays taken but nothing turned up.

"Then I was sent for further tests, and it was there that they diagnosed me.

"At one level I was relieved to find out at last what was wrong with me, though at that stage I really didn't have much of [a] clue about Motor Neuron Disease, and what the consequences of it are. I know a little more now. It wasn't a huge shock," he told the Sunday Independent.

"I have a great life and this is a challenge in that life. I have to say things are no worse than they were three weeks ago or before that. I am in the Dail three days a week and I am in my office today holding clinics and I'm keeping going.

"There is no use going into a corner and sulking because you only upset other people by doing that and I just feel better doing what I have always done and I am comfortable. That's my way of coping and I hope I will be doing that for a long long time to come.

"He told me that he didn't know how long I would last. He said it could be months or years. But he did say there were people who were coming in to see him five years after they were diagnosed who are in good shape so I would be hoping I would be one of those cases," said Fitzpatrick.