Male pattern baldness.
29 August 2012
Written by Stavroula Kanoni
I am a Postdoctoral Fellow studying in the ‘Genetics of complex traits in humans’ team under the guidance of Dr Panos Deloukas.
One of the projects that I am involved in is the genetic causes of male pattern baldness (known as androgenic alopecia). Male pattern baldness is the most common form of hair loss, affecting about 80 per cent of men. How the condition works is still a mystery, with a mix of genetic, environmental and lifestyle factors working together. We know that this form of hair loss is related to the levels of hormones called androgens, but exactly how is yet to be determined. For example all men develop male pattern baldness and some men are more affected than others. It is this puzzle that I am trying to help solve.
Apart from the cosmetic aspect of male pattern baldness, the condition may have an impact on other complex diseases such as coronary heart disease and prostate cancer, and factors that increase the risk of stroke and diabetes. So any insights we gain into androgenic alopecia may help us to better understand these diseases too.
I work in a team that uses large-scale genetic studies to help identify the different forms of genes involved in hair loss and tease apart how these gene variants work with the environment and lifestyle to cause hair loss. Up to now, just 13.7 per cent of the variance for androgenic alopecia has been explained through using population-based genetic association studies (genome-wide association studies or GWAS). In our latest study ‘Six Novel Susceptibility Loci for Early-Onset Androgenetic Alopecia and Their Unexpected Association with Common Disease’, published in PLOS Genetics, we looked for new gene variants that cause male pattern baldness and then looked to see if these variants were associated with common complex diseases.
We collected DNA samples from people with and without male pattern baldness, graded their level of hair loss and then compared this with their gene profile. My role was to help with the statistical analysis to work out the associations between gene profiles and levels of hair loss.
From this work we discovered six new areas of the genome that are associated with androgenic alopecia. As proof that the methods we used were trustworthy, our approach also identified two areas that had already been revealed to be associated with male pattern baldness. The most interesting finding was that one of the new genomic areas (known as 17q21.31) that we discovered has previously been found to be associated with Parkinson’s disease. To investigate this further we tested the association between early-onset male pattern baldness and the risk of Parkinson’s disease and found a significant link between the two conditions.
These findings have allowed us to delve further into genetic predisposition for male pattern baldness and the contributing biological pathways. We have already tested our work and replicated our findings, and we are now finding even more areas of the genome that are associated with androgenic alopecia (submitted unpublished data). We are also carrying out expression studies to see how and when the genes in these areas work to discover how they help to drive and maintain male pattern baldness.
Stavroula Kanoni is a Postdoctoral Fellow in the Genetics of complex traits in humans team at the Wellcome Trust Sanger Institute...more
Review Article: Rui Li et al. Six Novel Susceptibility Loci For Early Onset Androgenic Alopecia And Their Unexpected Association With Common Diseases. PLoS Genet 8 (5): e1002746.