Craig Hitchens Therapies - Health Online

Some men have more success than others in producing children, genetically speaking, that is.

Large European family, circa 1950s.

New findings have identified a gene that endows some men more reproductive prowess than their neighbor, according to an article by The Scientist. And the secret is a switch in amino acids within one gene – from an amino acid called methionine to valine.

Carole Ober of the University of Chicago, presented her findings at the Sackler Colloquium on Evolution in Health and Medicine in Washington, DC and she found that “men who carried two copies of the valine allele were 2.6 times more likely to conceive than men with two copies of the methionine allele at the same locus”. Man, that’s double the advantage!

The gene in the spotlight? CFTR, or cystic fibrosis transmembrane conductance regulator gene, where a mutation results in cystic fibrosis and male infertility.

Check out the complete article at The Scientist. You have to sign up to view the magazine, but I think the content is worth it.

Image: Newscom

A person with myopia can see closer objects better than distant objects (which appear blurred). A person with “high” myopia is so extremely nearsighted that only objects that are very near can be seen clearly, rendering the person as blind. Whereas a person with “mild” myopia may see object farther away as blurry but the person’s eyesight can still function.

A blurred vision.

Like most research in genetics, finding the genes for myopia has not been straightforward or easy. That’s because myopia has been defined, measured and classified in many different ways, in different studies. There’s high versus mild myopia or school versus adult myopia. How myopia is measured also differs from one group of scientists to another. And then there are the known and unknown environmental factors that influence how and why a person develops myopia! In scientific studies, it is often advised (and very helpful) to have the environment totally under controlled, and held the same across experiments. So this lack of uniformity between studies has prevented a more thorough and comprehensive analysis of the genetics. It’s rather overwhelming and frustrating!

Progress has been made in recent years, though. The more detailed article is found here, but in gist, potential genes for myopia have been identified:

Studies in “high” myopia found very strong evidence for autosomal myopia loci in chromosomes 18 (named MYP2 gene),  12 (MYP3) and 17. Studies in “mild” myopia identified several loci that may be partly responsible for myopia, including those in chromosome 11 (PAX6 gene region) and 22.

However, in many cases, further research really have to be done before someone can say “Eureka! I found it!”

image: flickr

When I tell people I used to research about the genetics of myopia (or nearsightedness),  one of the questions they ask is whether they’ll pass it to their children.

And I tell them there are other factors, “interactions” we call them, between our genes and our environment that determine if certain genes will express and/or be passed to our children.

Genes and Environment play roles in diseases. Image: Newscom

For example, mutations in the brca1 gene are highly associated with very high risks of breast cancer. A brca1 (breast cancer 1; on chromosome 7) is one of the genes in the body that suppresses tumors, by repairing damaged DNA. A mutation or defect in the gene produces a protein that can not repair DNA in other genes. A person with brca1 mutations has up to 80% risk of having breast cancer in one’s lifetime.

However, not everyone who has breast cancer has the brca1 mutation. So, there must be other causes or factors that brought about cancer, which may have nothing to do with brca1. Some of the environmental risk factors for developing breast cancer include recent use of birth control pills;  earlier start to the menstrual period; postmenstrual hormone therapy, alcohol and many others (see list here).

Disorders that may be affected by genes and environment (risk factors) include other cancers, autism and other behavioral conditions, eye diseases like myopia, asthma and allergies, heart diseases, obesity… the list goes on.  Genetics parlance refers to these as “complex disorders“.

In contrast, there are medical conditions that are 100% genetic, referred to as “Mendelian disoders“.  Having a defective gene means the person is affected by the disease, and passes the gene to his/her children. These disorders can be diagnosed before birth, usually through a genetic screening test at pregnancy. Examples include downs syndrome, cystic fibrosis, thalassemia, phenylketonuria,  sickle cell anemia, hemophilia A, Tay Sachs’ disease.

What I’d like to do this month is look at some of the complex disorders and the environment and genetic risk factors involved. We’ll start with myopia or nearsightedness, but let me know if there is a disease you’d like me to focus on as well.

Has your mom ever told you not to watch TV too closely? Have you been told as a child that reading too much (or cross-stitching too much) will hurt your eyes? That’s not too far out an idea, at all.

Severe myopia or nearsightnedness. Image: Flickr

Myopia or nearsightedness is a condition where one has trouble seeing objects that are farther away. Symptoms, usually developing in early childhood and teen years include squinting when trying to concentrate on an object far away, or holding an object very close to the face (to read, or to see it clearer). The person may want to sit very near the TV or computer close, and prefer to sit in the front of the class.

But does this mean that close-work and intensive reading cause eye problems?

Studies have shown that myopia is more common in some populations, such as the Ashkenazi Jews and Taiwanese where intensive studying and reading are encouraged; and in Singapore where certain jobs are visually-demanding. So certain kinds of exposures and tasks may contribute to myopia. BUT this is only part of the story.

Genes also play a major part, and plenty of studies already show that myopia is passed from parents to children. For example, myopia is more common in children of myopic parents than children of non-myopic parents.

So if scientists can identify myopia genes, treatments can specifically be created for children who are genetically more likely to develop myopia. Perhaps drug or gene therapies can even help make the condition less severe.

Tomorrow, we’ll look at some of the promising findings that point to genetic  factors of myopia.

image: Flickr

Competition is certainly good for us. One by one, the big league universities in the Boston neighborhood are going OPEN ACCESS.

Open access to publications. Image: sxc.hu

Open access publishing means that research works can be read (online) and used freely by the public without paying subscription fees to journals and publishers. I know personally how expensive it is to subscribe to just one journal, and the information from abstracts are really so limited that having more open access journals is just good for the science.

Last January, the University of California and publication giant Springer agreed to have articles written by UP-affiliated authors to be published immediately and in full, even if the rest of Springer’s articles remain subscription-only.

In early February, Harvard University’s Arts and Sciences agreed to support an open access system. Harvard faculty will also be required to only submit to journals that will publish their work online immediately after acceptance for publication. Following suit, Boston U and MIT independently announced that the work of faculties all across their universities will be accessible to the public for free.

Lest anyone get the wrong idea: Open access is not free. University libraries have to pay open-access journals to have their research published, and the cost for pre-pay memberships have gone up in the last few years. The public does not need to pay subscription fees, but the researchers do. So, MIT will now be storing their research materials at the MIT DSpace : http://dspace.mit.edu/. Boston and Harvard are also working on their own online repositories.

Hopefully, more universities will follow and set up their own websites, or partner with publishers to get the cost of publication lowered and open-access more available.

Image: sxc.hu