Molecular Genetics and Metabolism 83 (2004) 312–321 www.elsevier.com/locate/ymgme 1096-7192/$ - see front matter  2004 Elsevier Inc. All rights reserved. doi:10.1016/j.ymgme.2004.07.013 Decreased expression of lysyl hydroxylase 2 (LH2) in skin Wbroblasts from three Ehlers-Danlos patients does not result from mutations in either the coding or proximal promoter region of the LH2 gene  L.C. Walker a , A.S. Teebi b , J.C. Marini c , A. De Paepe d , F. Malfait d , P. Atsawasuwan e , M. Yamauchi e , H.N. Yeowell a a Division of Dermatology, Duke University Medical Ctr, Durham, NC, USA b Division of Clin Genetics, University of Toronto, Ont., Canada c Heritable Disorders Branch, NICHD, Bethesda, MD, USA d Center for Medical Genetics, Gent University Hospital, Gent, Belgium e Dental Research Center, University of North Carolina, Chapel Hill, NC, USA Received 12 May 2004; received in revised form 20 July 2004; accepted 23 July 2004 Available online 12 September 2004 Abstract The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of inherited connective tissue disorders characterized by tissue fragility, hyperelasticity of the skin and joint hypermobility. This phenotype, accompanied by kyphoscoliosis and/or ocular fragility, is present in patients with the autosomal recessive type VI form of EDS. These patients have signiWcantly decreased levels of lysyl hydroxylase (LH) activity, due to mutations in the LH1 gene. LH hydroxylates speciWc lysine residues in the collagen molecule that are precursors for the formation of cross-links which provide collagen with its tensile strength. No disorder has been directly linked to decreased expression of LH2 and LH3, two other isoforms of LH. This study describes 3 patients with mixed phenotypes of EDS, who have signiWcantly decreased mRNAs for LH2, but normal levels of LH1 and LH3 mRNAs, in their skin Wbroblasts. In contrast to the eVect of LH1 deWciency in EDS VI patients, the decreased expression of LH2 does not aVect LH activity, bifunctional collagen cross-links (measured after reduction as dihydroxylysinonorleucine (DHLNL) and hydroxylysinonorleucine (HLNL)), or helical lysine hydroxylation in these cell lines. Sequence analysis of full length LH2 cDNAs and 1 kb of the promoter region of LH2 does not show mutations that could explain the decreased expression of LH2. These results suggest that the deWciency of LH2 in these Wbroblasts may be caused by changes in other factors required for the expression of LH2.  2004 Elsevier Inc. All rights reserved. Keywords: Collagen cross-links; Ehlers-Danlos syndromes; Genetic heterogeneity; Lysyl hydroxylase2; Mutational analysis; Skin Wbroblasts Introduction The Ehlers-Danlos syndromes (EDS) are a heteroge- neous group of inherited connective tissue disorders characterized by joint hypermobility, skin extensibility and tissue fragility [1–3]. Although EDS was originally classiWed into 10 groups (characterized as EDS I–X) [3], it has since been simpliWed to 6 major types clearly deWned by major and minor diagnostic criteria [4]. The types include Classic (originally described as EDS I, II), Hypermobility (EDS III), Vascular (EDS IV), Kypho- scoliosis (EDS VI), Arthrochalasia (EDS VIIA,B), and Dermatosparaxis (EDS VIIC). Not included in this clas- siWcation are other forms of EDS associated speciWcally with periodontal disease [5] and progeria [6]. EDS VI, the Kyphoscoliosis type, is an autosomal recessive  This work was presented, in part, at the International Investigative Dermatology Meeting, Miami Beach, 2003 (H.N. Yeowell, L.C. Walk- er, A.S. Teebi, J. Invest. Dermatol. (Abstr.) 121 (2003) 602).