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One In 100 Carry Mutation For Heart Disease
mmmscience brings us news of a new study, published in Nature Genetics by an international team of scientists, that tells a scary story: globally, 1% of the population carry a gene mutation that is almost guaranteed to lead to some form of heart problems. On the Indian subcontinent, the prevalence is 4%. The mutation is a 25-letter deletion of DNA data on the heart protein gene MYBPC3, believed to have arisen in India 30,000 years ago. The researchers say that the mutation wasn't selected out of the population because its effects don't occur until after the childbearing years. The article mentions a prediction that "by 2010 India's population will suffer approximately 60% of the world's heart disease."
MYBPC3 = MY Blood Pressure Crap Crap Crap
Or better yet, childhood diagnosis with this particular condition would merit lifetime treatment with statins and aggressive control of other modifying factors. Prevent these kids from smoking, get them in a daily exercise habit, teach them a good diet, and monitor and aggressively treat for diabetes and hypertension if/when they appear. Except for the genetic test itself, the rest of that is cheaper than spit. Even in the US, the real cost of the blood tests and medicines would be less than $200 annually. Add two NP visits and its maybe $400 annually. The cost in India would obviously be even cheaper.
However what is expensive is the political will to prevent smoking in children. Its also politically expensive to have cheap and effective public health prevention programs. Heaven forbid you give medicines or pap smears to people who don't have insurance or money.... why.... it.... would be an ENTITLEMENT!
Shudder! Aiiigh! No, not that!
Wait, did that sound bitter?
Oooh, 1 in 100! Sounds scary! I'm at risk! Wait... lets apply some critical thinking to that number, shall we?
globally, 1% of the population carry a gene mutation that is almost guaranteed to lead to some form of heart problems.
World population is about 6.7B. Total number of people with this mutation in the world:
1% * 6.7B = 67M.
On the Indian subcontinent, the prevalence is 4%.
According to Wikipedia, the subcontinent "accounts for about 40 percent of Asia's population," which is 4B. Total number of people there with this mutation:
4% * 40% * 4B = 64M
So, the percentage of people NOT on the Indian subcontinent that carry this mutation is:
(67M - 64M) / (6.7B - 40%*4B) = 0.06%.
With such a great geographical disparity in incidence, using the global 1% figure to generate the headline of "1 in 100 carry mutation" is incredibly misleading.
The linked article is quite a bit better. It's titled "The heart disease mutation carried by 60 million," and focuses on this as being primarily an Indian problem. Somehow I'm not surprised to see kdawson as the editor on this one.
the thing i hate about these nonsense genetic claims, is that there is a 100% probability you are going to die of something. so claiming 60% of people will die of heart disease (because heart failure and cancer are what take out most of our population) is like pronouncing you have discovered people grow old and die. what would be more accurate, but you will never see them do it, is to tell us who will die a PREMATURE death due to heart disease. the reason they won't do it is there is far more to what kills you than genetics and admitting as much might see grant money going else where.
If you mod me down, I will become more powerful than you can imagine....
This is why I only invest in racist insurance companies...
Sleep your way to a whiter smile...date a dentist!
Good luck. Wishing you the best.
- Zav - Imagine a Beowulf cluster of insensitive clods...
Don't worry about carrying a 1% gene. Carrying a BigMac bag is far more likely to lead to heart attacks than genetics.
Engineering is the art of compromise.
The presence of this deletion in many Indian populations with varied geographical and ancestral backgrounds raises the question of how geographically widespread it is outside India. We therefore also analyzed 63 world population samples, comprising 2,085 indigenous individuals from 26 countries including all five continents. The 25-bp deletion was observed in Pakistan, Sri Lanka, Indonesia and Malaysia, (all heterozygotes) but was absent from other samples. Thus, the deletion is a common variant in individuals from South Asia, present in Southeast Asia, but undetectable elsewhere (Fig. 3 and Supplementary Table 5 online).
The supplementary materials give the sample sizes for each of the ethnic groups that were sampled and the number of deletion carriers. Most of the individual samples are small, but in the aggregate they do strongly suggest that the deletion is practically non-existent outside of South Asia and a few neighboring areas.
This does raise the question of how the media got this 1% prevalence estimate, unless I completely missed it in the article. In general, media outlets don't report the contents of peer-reviewed articles, they report the contents of press releases that accompany (or precede) the articles.
That's an interesting development in a well-known genetic heart defect. Myosin binding protein C is well known, and mutations in MYPBC3 are one of the most common causes of heart defects in humans (and cats).
If parents are comfortable with prenatal testing and abortion, this genetic defect could be effectively eliminated, in the same way that Down's syndrome has declined dramatically. In principle, the MYPBC3 defect would eventually be eliminated from the population.
MYPBC3 is a pretty cool protein, BTW. It connects the light chains and the heavy chains that make up muscle fibers. Obviously if the proteins that make up muscle fibers come apart you're going to have problems.
Here's a beautiful illustration http://pawpeds.com/pawacademy/health/mybpc3/figure1.jpg which shows how MYPBC3 comes out of the thick filament and holds onto the thin filament, sort of like this:
____________
====/==/====
(That illustration comes from an article here http://pawpeds.com/pawacademy/health/mybpc3/ about how Dr. Kittleson, in a stroke of nominative determinism, studied the defect in kittens.)
Another common cause of heart defects is protein called beta-myosin heavy chain (MYH7). MYH7 also comes out of the heavy chain. It's the one that looks like a bean pod. It looks a little like this:
____________
====P==P====
Here's a kewl animation of how it works http://www.sci.sdsu.edu/movies/actin_myosin.html with myosin walking along actin filaments. If you don't think this animation is funny, then molecular biology is not one of your aptitudes.
Or just do a Google image search for actin and myosin http://images.google.com/images?rls=ig&hl=en&q=actin+and+myosin
I'm sorry to say that the Wikipedia entries on this subject are not too user-friendly right now. Somebody should work on that.