Triple trouble.
An ability to process vitamin B-12 (3D model pictured) can lead to three different syndromes.
Credit: Karl Harrison/3Dchem.com
Posted on 04/03/2008 2:53:05 AM PDT by neverdem
Triple trouble.
An ability to process vitamin B-12 (3D model pictured) can lead to three different syndromes.
Credit: Karl Harrison/3Dchem.com
Scientists may have finally cracked a long-standing mystery about a rare genetic disorder--the inability to break down vitamin B-12--that can lead to three devastating conditions. A new study has linked them to mutations in different places on the same gene. At the same time, the finding could help solve the puzzle of how healthy people process the essential nutrient.
Vitamin B-12 plays a critical role in nerve function, the production of red blood cells and DNA, and other vital processes. So it's not surprising that people lacking a key protein for breaking down the vitamin so the cells can use it develop devastating health problems, including difficulty learning, psychosis, and anemia. But even though the same protein is affected in all patients, some develop a condition called homocystinuria, some develop another called methylmalonic aciduria, and still others develop both. Seeking to solve this riddle, a team led by geneticist David Rosenblatt of McGill University in Montreal, Canada, went searching for the cause of the disorder in cells obtained from seven patients.
Through a series of experiments, the researchers pinpointed what appeared to be the responsible gene, dubbed MMADHC. Compared to healthy people, people with any of the three conditions had mutations in MMADHC; in lab tests, normal copies of the gene delivered into the patients' cells restored those cells' ability to process vitamin B-12, the researchers report in the 3 April issue of the New England Journal of Medicine.
But the location of the mutations may explain the variety of the three conditions. Patients with methylmalonic aciduria had mutations on one end of the gene, which the team speculates would result in a semifunctional protein that leads to partial breakdown of vitamin B-12 and the buildup of byproducts that cause the disorder. Likewise, patients with homocystinuria had mutations on the opposite end of the gene, that would allow for partially processing another component of vitamin B-12, resulting in different byproducts likely to cause this condition, the researchers say. Patients with both conditions simultaneously had mutations near the middle of the gene that would cause an entirely dysfunctional protein--and trigger both disorders. Rosenblatt says that the scenario still needs to be confirmed.
The findings may lead the way to treatments, such as gene therapy, says Ralph Green, a hematologist at the University of California, Davis. Charles Venditti, a biochemical geneticist at the National Human Genome Research Institute in Bethesda, Maryland, says now that researchers know where to look, screenings of newborns may detect people with milder forms of the vitamin B-12 disorder who have up until now gone unrecognized; they could have fewer mutations or mutations that allow for a better-functioning protein.
The finding may also help scientists understand how cells of healthy people transport vitamin B-12 into the mitochondria, a process that until now has stumped them. The sequence of the MMADHC gene is similar--but not identical--to that of a transporter gene certain bacteria use for shuttling the vitamin around, so Rosenblatt speculates that the protein produced by the gene may be a novel transport system that human cells use to move vitamin B-12 into their mitochondria. That too, needs to be verified in experiments, Venditti and Green say.
Related sites
Genetic link for lung cancer identified
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I think I’ll have a steer for lunch.
These are disease related to protein folding. As such they may be of interest to the FR folders.
Very interesting. When I was a kid ( don’t ask! ) we had an Osteopathic physician who swore by B-complex shots as a general “pick-me-up,” and as I recall, you always felt like you could lick your weight in wildcats for a while after getting one.
Maybe the old guy ( Doc Marshall, RIP ) was on to something.
“protein folding?”
Moma alway said, “Don’t play with your food”.
bump
Carolyn
Thanks for the ping, neverdem. BUMP for Carolyn!
“Very interesting. When I was a kid ( don’t ask! ) we had an Osteopathic physician who swore by B-complex shots as a general “pick-me-up,” and as I recall, you always felt like you could lick your weight in wildcats for a while after getting one.”
“Maybe the old guy ( Doc Marshall, RIP ) was on to something.”
There are probably a lot of those old docs looking down from heaven, smiling and saying I told you so.
My Grandparents had wonderful gardens where they raised all types of fruits, vegies and lettuces. After the first freeze they both lost energy and got a little blue. Their family doc gave them B injections from about Thanksgiving until about May when their garden started providing daily goodies.
One of my corporate friends was and is still married to a uber liberal from Canada.
When they turned 60, she forced them into a severe vegan diet to save the world and them.
Her general health in a few months went to hell and so did her oral health.
He refused to retire at 65 and volunteered for a travel territory which required over night travel every other week.
Besides getting away from his increasing liberal wife, he was able to eat lunch every day with meat. Then, every two weeks he went out of town and knew the best steak houses in his territory. He finally quit at age 70.
A year or so later after his retirement, we found out that his wife had been told by her doctors, dentist and oral surgeon a few months before he retired that if she didn’t give up her vegan diet, she was in for some really miserable years. So she started cooking real food, and he retired a few months later.
She is very healthy now and eats meat a couple of times each day. Unfortunately the good diet hasn’t changed her liberal outlook.
Why not? Done. I like your attitude. My sister was diagnosed with colorectal adenocarcinoma. She's taking 4000 units of vitamin D3 daily for it per her nutritionist. It can help the immune system, although the results seem scattered depending on the cancer and other variables. Chemo went very poorly for my sister. You may want to check it out on PubMed.
There are four types of lung cancer: squamous cell carcinoma, adenocarcinoma, large cell carcinoma and small cell, also known as oat cell, carcinoma. It would help searching the medical literature if you knew what kind it was. Once it is warm enough to get plenty of sunshine, I would hold the oral supplements. Vitamin D Boning up on the sunshine vitamin
When I use PubMed I usually use the Boolean operators and, or and not with paretheses, e.g. (lung and squamous cell carcinoma) and vitamin D3
I wonder if there was a permanent neurological deficit? Thanks for the story.
“I wonder if there was a permanent neurological deficit?”
One of these days, we will be able to do a PET scan or something similiar on liberals and find out that most were born with permanent neurological deficits or defaults.
They probably do have something neurologically wrong with them. Seriously.
Every liberal I’ve met seemed spacey, hypersensitive, or plain weird. Their thinking is distorted. I would wager quite a few have chemical imbalances, learning disabilities, or actual mental illnesses.
“I would wager quite a few have chemical imbalances, learning disabilities, or actual mental illnesses.”
Probably more than quite a few have the three problems you sited.
There are some interesting report coming out how our brains are hard wired, trend us to be believers in God or non believers, and liberal and conservative.
This does not include those, who were brainwashed into being liberals in school, college or by peer pressure. Some of those people can be changed when a life experience comes knocking at the door like 9/11, loss of a loved one or a harmful betrayal by a liberal.
Thanks for the ping.
Prayers offered up for your return to full health, Carolyn.
We’re starting to hear more and more stories about B-12 injections - athletes and, yes, Hollywood actor-types.
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