Marco Sazzini1, Paolo Garagnani2, Stefania Sarno1, Sara De Fanti1, Teresa Lazzano3, Daniele Yang Yao3, Alessio Boattini1, Giulia Pazzola4, Sally Maramotti5, Luigi Boiardi4, Claudio Franceschi2, Carlo Salvarani4, Donata Luiselli1. 1. Laboratory of Molecular Anthropology; and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, Italy. 2. Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna; Interdepartmental Center "L. Galvani", University of Bologna; and Applied Biomedical Research Center, S. Orsola-Malpighi General Hospital, Bologna, Italy. 3. Laboratory of Molecular Anthropology, Department of Biological, Geological and Environmental Sciences, University of Bologna, Italy. 4. Rheumatology Unit, Istituto di Ricovero e Cura a Carattere Scientifico, Azienda Ospedaliera Arcispedale Santa Maria Nuova, Reggio Emilia, Italy. 5. Rheumatology Unit, Istituto di Ricovero e Cura a Carattere Scientifico, Azienda Ospedaliera Arcispedale Santa Maria Nuova, Reggio Emilia; and Translational Research Laboratory, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy.
Abstract
OBJECTIVES: Behçet's disease is a multifactorial vasculitis that shows its highest prevalence in geographical areas historically involved in the Silk Road, suggesting that it might have originated somewhere along these ancient trade routes. This study aims to provide a first clue towards genetic evidence for this hypothesis by testing it via an anthropological evolutionary genetics approach. METHODS: Behçet's disease variation at ancestry informative mitochondrial DNA control region and haplogroup diagnostic sites was characterised in 185 disease subjects of Italian descent and set into the Eurasian mitochondrial landscape by comparison with nearly 9,000 sequences representative of diversity observable in Italy and along the main Silk Road routes. RESULTS: Dissection of the actual genetic ancestry of disease individuals by means of population structure, spatial autocorrelation and haplogroup analyses revealed their closer relationships with some Middle Eastern and Central Asian groups settled along the Silk Road than with healthy Italians. CONCLUSIONS: These findings support the hypothesis that the Behçet's disease genetic risk has migrated to western Eurasia in parallel with ancestry components typical of Silk Road-related groups. This provided new insights that are useful to improve the understanding of disease origins and diffusion, as well as to inform future association studies aimed at properly accounting for the actual genetic ancestry of the examined Behçet's disease samples in order to minimise the detection of spurious associations and to improve the identification of genetic variants with actual clinical relevance.
OBJECTIVES: Behçet's disease is a multifactorial vasculitis that shows its highest prevalence in geographical areas historically involved in the Silk Road, suggesting that it might have originated somewhere along these ancient trade routes. This study aims to provide a first clue towards genetic evidence for this hypothesis by testing it via an anthropological evolutionary genetics approach. METHODS: Behçet's disease variation at ancestry informative mitochondrial DNA control region and haplogroup diagnostic sites was characterised in 185 disease subjects of Italian descent and set into the Eurasian mitochondrial landscape by comparison with nearly 9,000 sequences representative of diversity observable in Italy and along the main Silk Road routes. RESULTS: Dissection of the actual genetic ancestry of disease individuals by means of population structure, spatial autocorrelation and haplogroup analyses revealed their closer relationships with some Middle Eastern and Central Asian groups settled along the Silk Road than with healthy Italians. CONCLUSIONS: These findings support the hypothesis that the Behçet's disease genetic risk has migrated to western Eurasia in parallel with ancestry components typical of Silk Road-related groups. This provided new insights that are useful to improve the understanding of disease origins and diffusion, as well as to inform future association studies aimed at properly accounting for the actual genetic ancestry of the examined Behçet's disease samples in order to minimise the detection of spurious associations and to improve the identification of genetic variants with actual clinical relevance.