Funding sources The study was supported by the Deutsche Forschungsgemeinschaft (FOR 423) and the Alfried Krupp von Bohlen und Halbach-Stiftung. J.A.E. was supported by a National Health & Medical Research Council (Australia) Capacity Building Grant in Population Health.
Susceptibility variants on chromosome 7p21.1 suggest HDAC9 as a new candidate gene for male-pattern baldness
Version of Record online: 24 NOV 2011
© 2011 The Authors. BJD © 2011 British Association of Dermatologists
British Journal of Dermatology
Volume 165, Issue 6, pages 1293–1302, December 2011
How to Cite
Brockschmidt, F.F., Heilmann, S., Ellis, J.A., Eigelshoven, S., Hanneken, S., Herold, C., Moebus, S., Alblas, M.A., Lippke, B., Kluck, N., Priebe, L., Degenhardt, F.A., Jamra, R.A., Meesters, C., Jöckel, K.-H., Erbel, R., Harrap, S., Schumacher, J., Fröhlich, H., Kruse, R., Hillmer, A.M., Becker, T. and Nöthen, M.M. (2011), Susceptibility variants on chromosome 7p21.1 suggest HDAC9 as a new candidate gene for male-pattern baldness. British Journal of Dermatology, 165: 1293–1302. doi: 10.1111/j.1365-2133.2011.10708.x
Conflicts of interest None declared.
F.F.B. and S.H. have contributed equally to this work.
- Issue online: 24 NOV 2011
- Version of Record online: 24 NOV 2011
- Accepted manuscript online: 27 OCT 2011 03:50PM EST
- Accepted for publication 20 October 2011
Background Male-pattern baldness (androgenetic alopecia, AGA) is the most common form of hair loss among humans. Research has shown that it is caused by genetic factors. Numerous studies have unequivocally identified two major genetic risk loci for AGA: the X-chromosomal AR/EDA2R locus, and the PAX1/FOXA2 locus on chromosome 20.
Objectives To identify further candidate genes for AGA, and thus gain further insights into this phenotype.
Methods A German sample of 581 severely affected cases and 617 controls was used to perform a genome-wide association study. The identified associated locus was further analysed by fine-mapping, and then independently replicated in an Australian sample. Expression and pathway analyses were performed to characterize the susceptibility gene identified.
Results The most significant association signal was obtained for rs756853 (P = 1·64 × 10−7), which is located intronically in the histone deacetylase 9 (HDAC9) gene. Fine-mapping and a family-based analysis revealed that rs756853 and the 6-kb distal rs2249817 were the most highly associated single nucleotide polymorphisms. The association finding was replicated in an independent Australian sample, when the analysis was restricted to severely affected cases and unaffected controls (P = 0·026). Analysis of rs2249817 in a combined sample of severely affected German and Australian cases and unaffected controls revealed a strong association signal (P = 9·09 × 10−8). Tissue expression studies demonstrated HDAC9 expression in various tissues, including tissues of relevance to AGA. No strong genotypic effects were observed in genotype-specific expression or splice studies. Pathway analyses supported the hypothesis that HDAC9 plays a functional role in AGA via interaction with the AR gene.
Conclusions The present study suggests that HDAC9 is the third AGA susceptibility gene.