14 DAY TRIAL // Being too short or too tall impacts your welfare, from social life to sex life. That's why, scientists are struggling to find out which are the genes that influence our height. In a research published in the journal "Nature Genetics" and made on over 35,000 subjects, an international team discovered that genes connected to osteoarthritis could have a minor role in determining our height.
These genes are found in an area of the human genome controlling the activity of a gene for growth differentiation factor 5 (GDF5). This protein is connected to cartilage development. Rare mutations in the GDF5 gene were connected to skeletal development disorders, and more common mutations to proneness to osteoarthritis of the hip and knees, in populations from Europe and Asia.
"The common variants we identified are associated with both short stature and, as described previously, increased risk of osteoarthritis. Our findings suggest a link between the genetic basis of height and osteoarthritis, potentially mediated through alterations in bone growth and development", said senior author Dr Karen L. Mohlke, of the University of North Carolina, Chapel Hill.
As these mutations are responsible for only a small percentage of the height genetics, much more research is required for having a complete image of it. Height is influenced also by prenatal environment and diet, but genes are 80 % responsible for how tall you are. But, the GDF5 gene and the newly detected HMGA2 gene are less than 1 % responsible for the whole human height variation.
GDF5 counts with an average height difference of about 0.4 cm (0.14 inch), with a range of 0.3 cm to 1.4 cm (0.12 to 0.55 inches), connected to the population and the possession of one or two copies of the "taller" allele (variant) of the gene. Differences were not connected to gender, weight or body mass index.
"Many of the genetic variants involved in height likely will have only small effects, so it's going to take a lot of work involving very large sample sets to uncover all of them", said co-author Dr. Francis S. Collins, director of NHGRI's Genome Technology Branch.
Osteoarthritis, experienced by about 21 million people only in US, is a degenerative joint condition, affecting cartilage, and it is mainly experienced by older people. The mutation decreasing the synthesis of the GDF5 protein could lower the cartilage proportion in the spine and limb joints, causing both a modest height decrease and higher vulnerability to osteoarthritis. The team surveyed each subject's genome, searching for selected markers of genetic variation. If average height differs for individuals possessing specific alleles, this means that something in that chromosome affected height.
The impact of over 2 million alleles was checked. The markers show the "culprit" genome area, but they do not impact directly the trait, that's why investigating the area was required for detecting the gene connected to the trait. The study was made on the genomes of about 4,300 people from Sardinia, over 2,300 Finns, over 24,000 White Americans and about 4,000 African-Americans.