A study by researchers at Harvard Medical School found that some common foot disorders, such as bunions, claw toe and hammer toe might be hereditary.
The study, led by Dr. Marian Hannan, examined 1,370 individuals in order to determine if certain foot disorders where passed on from generation to generation. The average age of a study participant was 66 years old, and 57% of them were female.
In order to determine which participants suffered from foot ailments, researchers conducted individual foot exams on each patient. The exams tested for hallux valgus (aka bunions), plantar soft tissue atrophy, and lesser toe deformities. Once symptoms were identified, researchers used software that analyzes genetic familial data to provide an estimated likelihood of heritability.
Results
Of the participants in the study, 31% suffered from bunions, 30% from lesser toe deformities, and 28% from plantar soft tissue atrophy. When compared to the familial data, researchers found:
- Bunions were found to be highly heritable in relation to age and sex.
- Lesser toe deformities were found to be highly heritable in relation to age and sex.
- Plantar soft tissue atrophy did not demonstrate significant heritability in the study.
Bunions and lesser toe deformities are some of the most common foot ailments among white men and women. Over half of the older population in America and Europe suffer from one of these common foot disorders. Dr. Hannan said she believes her study can be used as a way to predict the likelihood that someone may become afflicted with a disorder later in life.
“Our study is the largest investigation of the heritability of common foot disorders in older adults, confirming that bunions and lesser toe deformities are highly inheritable in Caucasian men and women of European descent,” said Dr. Hannan. “These new findings highlight the importance of furthering our understanding of what causes greater susceptibility to these foot conditions, as knowing more about the pathway may ultimately lead to early prevention or early treatment.”
Dr. Silverman comments
The study notes an increasing heritability of bunion and lesser toe deformities. This study’s flaw is its strongest point, interestingly enough.
The study fails, as in most genetic studies do, to address phenotype vs. genotype. A phenotype is an observable expression of the genes, like hair color for example. Genotypes are a major influencing factor in the expression of phenotypes, but it is important to remember that it is not the only factor. Two organisms with the same genotypes normally have different phenotypes.
It’s too hard to study genotypes despite all our knowledge of DNA, as there is no one gene that codes for ailments like bunions or hammer toe, but phenotypes can be evaluated.
Here is the kicker, we know that in the present environment in which Americans expose their feet (especially women), we can predict bunion and hammer toe deformities to develop very reliably by looking at the parents. How would one differentiate genetics from the environment? Nature vs. Nurture? By studying populations of people who don’t wear shoes or who don’t wear closed toed shoes.
Right now, this study tells us “women who wear American style footwear have their parents feet to look forward to”. Perhaps the conclusion is strong enough for some, but it doesn’t mean that if women make different choices in footwear they will necessarily avoid developing these deformities.
Related source: News.Medical.net