Height Linked to Genetic Variants

The largest genome-wide association study conducted, which was published in the journal Nature, used DNA from nearly 5 million individuals from 281 contributing studies. Of the individuals used, more than one million were of non-European heritage, which included African, East Asian, Hispanic, and South Asian. There were 12,111 genetic variants that offered a strong genetic predictor of height in individuals. The identified variants accounted for 40% of height variance in individuals of European ancestry, with 10-20% of height variance in non-European individuals.

The findings could help doctors identify individuals who are not able to reach their genetically predicted height, and could help in the diagnosis of hidden genetic conditions and diseases that impact height. The research done also has the "blueprint" for how genome-wide studies can be used to identify the biology and hereditary components of diseases.

After reading the article, I was astonished to find that there are many different variants and genes that affect how tall a person is. From previous knowledge, as well as the use of the internet, I knew that tall parents produced tall offspring, short parents produced short offspring, and a mix produced offspring of medium height. Though, I did not know that there were more than 12,000 variants that do so.

Genetic Variants Linked to Height

For decades, scientists have been in search of the common genetic factors influencing one's height and have had no luck. After studying almost 5.4 million people’s DNA, a team of geneticists have conducted the largest genome-wide association study of its kind, identifying over 12,000 height influencing genetic variants. Depending on the person’s ancestry, up to 40 percent of all variation in height can be explained by these variants typically clustering around the sections of genome associated with skeletal growth. This almost 20-year study has resulted in the discovery of the majority of genetic variation linked to height and the growing sample size can inform us about traits controlled by multiple genes.

     This monumental study can one day help physicians identify deficiencies and hidden diseases in individuals who are not meeting their predicted genetic height. The current outcome of the genome-wide association studies (GWAS) demonstrates its importance in the biological basis and heritability of diseases. Together, GWAS and 23andme were able to collect data from seven times more people than in original studies. The results revealed common single nucleotide polymorphisms (SNPs) associated with height. These SNPs make up 40 percent of variation in height of European descent and 10 – 20 percent for those not of European ancestry. This difference is likely due to the study composition being mostly European individuals, so there is a lack of diversity in the study. Increasing the non-European population in the study could prove the study to be more accurate in its findings of genome height influencing regions. Additionally, a more diverse cohort could help determine if specific groups are more likely to have certain genetic variants. With the knowledge collected, further research can be conducted to trace the effects of individual variants on height and could reveal correlations with other common conditions influenced by multiple genes.  

Human Height Genetics Revealed

Genetic Investigation of Anthropometric Traits conducted an international study of 700,000 people revealed 83 genetic variations effect height. The study used a technology called ExomeChip to study 200,000 gene variants examining bone cartilage, and growth hormone production. Of these, STC2 was found to have DNA changes that control height.  Activation of STC2 was found to increase height by 1-2cm and this sheds light on how growth works. Scientists hope to use this to predict growth patterns of diseases such as diabetes and schizophrenia to be able to provide precision treatment.

While this may answer the genetic reasons for height gain and growth, the STC2 and other growth factors can also be activated and extended due to environmental influence which can either activate or hinder growth. I think diet, exercise, and nutrition is a severely overlooked factor in human height/growth. In eastern Asian for example, the average height has grown significantly over the years most likely due to the increased availability of nutritious food and modern lifestyle.
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature21039.html
http://www.medicalnewstoday.com/articles/315620.php