The Massapequa, N.Y., couple have two healthy sons, who are carriers, but whose wives are not, and four healthy grandchildren.
For years, Altman was able to get around with a walker until he had to drop out of a clinical trial for a new drug because of debilitating side effects. After that, he said he lost 40 pounds and so much muscle that he could no longer stand on his own.
"Between the two of us we handle it and we lead kind of a normal life," said Lorrie. "But we have no idea what the future will bring."
Altman works at Nassau University Medical Center in the security monitoring department. He raises funds for about 11 different non-profit organizations, including NTSAD, and has given presentations to the Boy Scouts and senior citizens.
Much of the public work has now ended, as his speech has become more incomprehensible because the degeneration of the nerves that control his respiratory muscles.
"Stewart has a good way of just living in the moment," said his wife, who met Altman in college. "But the worst part for him is his speech. He is such a social, outgoing person."
He has faced discrimination along the way, especially after leaving a Manhattan engineering job because he couldn't climb the subway stairs.
"He has such a hard time getting a job -- it was devastating," said Lorrie Altman. "On paper, he looked so good, but his speech was terrible. He has a college degree and isn't stupid, but all people see is the wheelchair."
Doctors say that many with the milder adult form of Tay-Sachs can lead full lives, despite their disability. And science is getting closer to finding treatments for this devastating disease.
Dr. Edwin Kolodny, former department chair and now professor of neurology at New York University School of Medicine, has been a leader in the field for 30 years. He first helped identify the role of the enzyme Hex-A and later tested more than 30,000 young adults in the 1970s and 1980s.
Today, he and others are involved in the promising gene therapy studies involving first mice, then cats and now sheep. Injecting genes into the brains of Jacob lambs has doubled their life span.
Clinical trials on humans are set to begin as soon as researchers can raise another $700,000 -- in addition to a grant from the National Institutes of Health -- to manufacture the vectors required to insert the genes into the body.
"It seems like every parent in the world would like to be part of the trial," said Kolodny. "And there are reasons to think there will be success here, especially for children who have a slightly later onset and not the classic form Tay-Sachs."
In the past, infantile Tay-Sachs has seen most of the medical attention. "These children have zero quality of life," he said.
Those with mild mutations, like Altman, who have 5 to 10 percent of Hex A enzyme activity, "sometimes lead full lives," according to Kolodny. "Intellectually, most of their cognitive function is retained. We have patients who are lawyers and accountants."
Pre-conception testing is still the gold standard for fighting the disease. "If your parents don't have the same recessive genes, you are home free," he said.
Those identified as at risk for having a child with Tay-Sachs can decide to adopt or conceive through in vitro fertilization, where geneticists can test the embryos before implantation to ensure the child will be disease-free.
Doctors can also do prenatal genetic testing and if the fetus is affected, the decision is up to the parents whether or not they want to terminate the pregnancy. "Three out of four times, they are reassured they have a normal child," said Kolodny.