Bi-allelic Alterations in AEBP1 Lead to Defective Collagen Assembly and Connective Tissue Structure Resulting in a Variant of Ehlers-Danlos Syndrome

Patrick R. Blackburn, Zhi Xu, Kathleen E. Tumelty, Rose W. Zhao, William J. Monis, Kimberly G. Harris, Jennifer M. Gass, Margot A. Cousin, Nicole J. Boczek, Mario V. Mitkov, Mark A. Cappel, Clair A. Francomano, Joseph E. Parisi, Eric W. Klee, Eissa Faqeih, Fowzan S. Alkuraya, Matthew D. Layne, Nazli B. McDonnell, Paldeep S. Atwal

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


AEBP1 encodes the aortic carboxypeptidase-like protein (ACLP) that associates with collagens in the extracellular matrix (ECM) and has several roles in development, tissue repair, and fibrosis. ACLP is expressed in bone, the vasculature, and dermal tissues and is involved in fibroblast proliferation and mesenchymal stem cell differentiation into collagen-producing cells. Aebp1−/− mice have abnormal, delayed wound repair correlating with defects in fibroblast proliferation. In this study, we describe four individuals from three unrelated families that presented with a unique constellation of clinical findings including joint laxity, redundant and hyperextensible skin, poor wound healing with abnormal scarring, osteoporosis, and other features reminiscent of Ehlers-Danlos syndrome (EDS). Analysis of skin biopsies revealed decreased dermal collagen with abnormal collagen fibrils that were ragged in appearance. Exome sequencing revealed compound heterozygous variants in AEBP1 (c.1470delC [p.Asn490_Met495delins(40)] and c.1743C>A [p.Cys581]) in the first individual, a homozygous variant (c.1320_1326del [p.Arg440Serfs3]) in the second individual, and a homozygous splice site variant (c.1630+1G>A) in two siblings from the third family. We show that ACLP enhances collagen polymerization and binds to several fibrillar collagens via its discoidin domain. These studies support the conclusion that bi-allelic pathogenic variants in AEBP1 are the cause of this autosomal-recessive EDS subtype.

Original languageEnglish (US)
Pages (from-to)696-705
Number of pages10
JournalAmerican journal of human genetics
Issue number4
StatePublished - Apr 5 2018


  • ACLP
  • AEBP1
  • Aebp1-null mice
  • Ehlers-Danlos syndrome
  • aortic carboxypeptidase-like protein
  • collagen polymerization
  • connective tissue disorders
  • discoidin domain
  • exome sequencing
  • extracellular matrix

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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