title: The distinct features of microbial 'dysbiosis' of Crohn's disease do not occur to the same extent in their unaffected, genetically-linked kindred.
abstract: OBJECTIVE
  Studying the gut microbiota in unaffected relatives of people with Crohn's disease (CD) may advance our understanding of the role of bacteria in disease aetiology.
  
  
  METHODS
  Faecal microbiota composition (16S rRNA gene sequencing), genetic functional capacity (shotgun metagenomics) and faecal short chain fatty acids (SCFA) were compared in unaffected adult relatives of CD children (CDR, n = 17) and adult healthy controls, unrelated to CD patients (HUC, n = 14). The microbiota characteristics of 19 CD children were used as a benchmark of CD 'dysbiosis'.
  
  
  RESULTS
  The CDR microbiota was less diverse (p = 0.044) than that of the HUC group. Local contribution of β-diversity analysis showed no difference in community structure between the CDR and HUC groups. Twenty one of 1,243 (1.8%) operational taxonomic units discriminated CDR from HUC. The metagenomic functional capacity (p = 0.207) and SCFA concentration or pattern were similar between CDR and HUC (p>0.05 for all SCFA). None of the KEGG metabolic pathways were different between these two groups. Both of these groups (HUC and CDR) had a higher microbiota α-diversity (CDR, p = 0.026 and HUC, p<0.001) with a community structure (β-diversity) distinct from that of children with CD.
  
  
  CONCLUSIONS
  While some alterations were observed, a distinct microbial 'dysbiosis', characteristic of CD patients, was not observed in their unaffected, genetically linked kindred.
authors.affiliation: School of Engineering, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Umer Zeeshan
authors.initials: UZ
authors.lastname: Ijaz
authors.affiliation: Warwick Medical School, University of Warwick, Warwick, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Quince
authors.affiliation: Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow Royal Infirmary, Glasgow, United Kingdom.
authors.forename: Laura
authors.initials: L
authors.lastname: Hanske
authors.affiliation: Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Nick
authors.initials: N
authors.lastname: Loman
authors.affiliation: Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Szymon T
authors.initials: ST
authors.lastname: Calus
authors.affiliation: Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow Royal Infirmary, Glasgow, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Bertz
authors.affiliation: Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow Royal Infirmary, Glasgow, United Kingdom.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Edwards
authors.affiliation: Gastroenterology Unit, Glasgow Royal Infirmary, Glasgow, United Kingdom.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Gaya
authors.affiliation: Department of Paediatric Gastroenterology, Hepatology and Nutrition, Royal Hospital for Children, Glasgow, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Hansen
authors.affiliation: Department of Paediatric Gastroenterology, Hepatology and Nutrition, Royal Hospital for Children, Glasgow, United Kingdom.
authors.forename: Paraic
authors.initials: P
authors.lastname: McGrogan
authors.affiliation: Department of Paediatric Gastroenterology, Hepatology and Nutrition, Royal Hospital for Children, Glasgow, United Kingdom.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Russell
authors.affiliation: Human Nutrition, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow Royal Infirmary, Glasgow, United Kingdom.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Gerasimidis
mesh_terms: D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002648:Child; D003424:Crohn Disease / Q000235:genetics / Q000382:microbiology*; D064806:Dysbiosis / Q000209:etiology / Q000235:genetics / Q000382:microbiology*; D005192:Family Health; D005232:Fatty Acids, Volatile / Q000032:analysis; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005260:Female; D000069196:Gastrointestinal Microbiome; D006801:Humans; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis; D008297:Male; D053858:Metabolic Networks and Pathways; D056186:Metagenomics; D010290:Parents; D021521:Ribotyping; D035781:Siblings
chemical_list: D005232:Fatty Acids, Volatile; D039841:Leukocyte L1 Antigen Complex