Genetics of Bone Formation and Bone Density
In humans aging is invariably accompanied by changes in skin and bone. While age-related skin wrinkling is rather a cosmetic problem, age-related bone loss results in a increased susceptibility to fractures and thus a significant disease burden. To elucidate the molecular processes that govern aging in these tissues, we studied a group of recessively inherited diseases collectively characterized by the combination of wrinkly skin and osteoporotic bone. Over the last years we have been able to identify disease causing mutations in three different genes, two of which are involved in the Golgi networkand mitochondria.
The bone mass of our body is regulated via complex feedback loops, loss of bone results in osteoporosis, a condition that is invariably associated with ageing and that results in an increased susceptibility to fractures. To elucidate the molecular processes that govern osteoporosis and ageing in bone, we are studying the genetic causes of abnormal bone density. We have been able to identify disease-causing mutations in several different genes (GORAB, ATP6V0A2, PYCR1, WNT1), two of which are involved in the Golgi network. Our findings provide new insights into the molecular mechanisms of skin ageing and osteoporosis. Increased susceptibility to apoptosis and/or senescence appears to be an important trigger for age-related changes in skin and bone. Current studies focus on the identification of novel disease genes and the characterization of pathogenic mechanisms in osteoporosis, in particular, related to senescence. Studies are being carried out to determine the prevalence of mutations in patients with early-onset osteoporosis.
Selected publications
1.
Luther J, Yorgan TA, Rolvien T, Ulsamer L, Koehne T, Liao N, Keller D, Vollersen N, Teufel S, Neven M, Peters S, Schweizer M, Trumpp A, Rosigkeit S, Bockamp E, Mundlos S, Kornak U, Oheim R, Amling M, Schinke T, David JP.
Wnt1 is an Lrp5-independent bone-anabolic Wnt ligand.
Sci Transl Med. 2018 Nov 7;10(466). pii: eaau7137
2.
Chan WL, Steiner M, Witkos T, Egerer J, Busse B, Mizumoto S, Pestka JM, Zhang H, Hausser I, Khayal LA, Ott CE, Kolanczyk M, Willie B, Schinke T, Paganini C, Rossi A, Sugahara K, Amling M, Knaus P, Chan D, Lowe M, Mundlos S, Kornak U.
Impaired proteoglycan glycosylation, elevated TGF-β signaling, and abnormal osteoblast differentiation as the basis for bone fragility in a mouse model for gerodermia osteodysplastica.
PLoS Genet. 2018 Mar 21;14(3):e1007242
3.
Flöttmann R, Kragesteen BK, Geuer S, Socha M, Allou L, Sowińska-Seidler A, Bosquillon de Jarcy L, Wagner J, Jamsheer A, Oehl-Jaschkowitz B, Wittler L, de Silva D, Kurth I, Maya I, Santos-Simarro F, Hülsemann W, Klopocki E, Mountford R, Fryer A, Borck G, Horn D, Lapunzina P, Wilson M, Mascrez B, Duboule D, Mundlos S, Spielmann M.
Noncoding copy-number variations are associated with congenital limb malformation.
Genet Med. 2018 Jun;20(6):599-607. Epub 2017 Oct 12
4.
Ehmke N, Graul-Neumann L, Smorag L, Koenig R, Segebrecht L, Magoulas P, Scaglia F, Kilic E, Hennig AF, Adolphs N, Saha N, Fauler B, Kalscheuer VM, Hennig F, Altmüller J, Netzer C, Thiele H, Nürnberg P, Yigit G, Jäger M, Hecht J, Krüger U, Mielke T, Krawitz PM, Horn D, Schuelke M, Mundlos S, Bacino CA, Bonnen PE, Wollnik B, Fischer-Zirnsak B, Kornak U.
De Novo Mutations in SLC25A24 Cause a Craniosynostosis Syndrome with Hypertrichosis, Progeroid Appearance, and Mitochondrial Dysfunction.
Am J Hum Genet. 2017 Nov 2;101(5):833-843
5.
Seifert W, Posor Y, Schu P, Stenbeck G, Mundlos S, Klaassen S, Nürnberg P, Haucke V, Kornak U, Kühnisch J.
The progressive ankylosis protein ANK facilitates clathrin- and adaptor-mediated membrane traffic at the trans-Golgi network-to-endosome interface.
Hum Mol Genet. 2016. pii: ddw230.
6.
Al-Bughaili M, Neuhann TM, Flöttmann R, Mundlos S, Spielmann M, Kornak U, Fischer-Zirnsak B.
A de novo 1q23.3-q24.2 deletion combined with a GORAB missense mutation causes a distinctive phenotype with cutis laxa.
J Hum Genet 2017 Feb;62(2):325-328
7.
Fischer-Zirnsak B, Escande-Beillard N, Ganesh J, Tan YX, Al Bughaili M, Lin AE, Sahai I, Bahena P, Reichert SL, Loh A, Wright GD, Liu J, Rahikkala E, Pivnick EK, Choudhri AF, Krüger U, Zemojtel T, van Ravenswaaij-Arts C, Mostafavi R, Stolte-Dijkstra I, Symoens S, Pajunen L, Al-Gazali L, Meierhofer D, Robinson PN, Mundlos S, Villarroel CE, Byers P, Masri A, Robertson SP, Schwarze U, Callewaert B, Reversade B, Kornak U.
Recurrent De Novo Mutations Affecting Residue Arg138 of Pyrroline-5-Carboxylate Synthase Cause a Progeroid Form of Autosomal-Dominant Cutis Laxa.
Am J Hum Genet. 2015 Sep 3;97(3):483-92
8.
Kornak U, Mademan I, Schinke M, Voigt M, Krawitz P, Hecht J, Barvencik F, Schinke T, Gießelmann S, Beil FT, Pou-Serradell A, Vílchez JJ, Beetz C, Deconinck T, Timmerman V, Kaether C, De Jonghe P, Hübner CA, Gal A, Amling M, Mundlos S, Baets J, Kurth I.
Sensory neuropathy with bone destruction due to a mutation in the membrane-shaping atlastin GTPase 3.
Brain. 2014 Mar;137(Pt 3):683-92. Epub 2014 Jan 22.
9.
Kühnisch J, Seto J, Lange C, Schrof S, Stumpp S, Kobus K, Grohmann J, Kossler N, Varga P, Osswald M, Emmerich D, Tinschert S, Thielemann F, Duda G, Seifert W, El Khassawna T, Stevenson DA, Elefteriou F, Kornak U, Raum K, Fratzl P, Mundlos S, Kolanczyk M.
Multiscale, converging defects of macro-porosity, microstructure and matrix mineralization impact long bone fragility in NF1.
PLoS One. 2014 Jan 21;9(1):e86115. eCollection 2014.