Genome Study in Constitutional Thinness (GENOSCANN)

Constitutional thinness (CT) is a recently defined entity as a differential diagnosis of anorexia nervosa (AN), considered to be the most frequent cause of low body mass index (BMI) in young women. CT subjects present no AN psychiatric traits, preserved menses, no biological signs of undernutrition and balanced energy metabolism despite a Body Mass Index (BMI) <17 kg / m².

CT familial aggregation, low body mass without a hormonal explanation, and specific appetite regulation profile suggest a specific genetic profile in these subjects.

Objective: A family linkage study in order to identify genes involved in the constitutional thinness phenotype by using genome wide scan (GWAS) techniques Studied population: Fifty families including at least one well phenotyped CT index case (grade 2 or 3 of thinness according WHO classification). Blood or saliva is sampled for DNA extraction.

Perspectives: Revealing eventual abnormalities could lead to a more precise diagnosis of constitutional thinness and new hypothesis in understanding extreme bodyweight mechanisms.

Study Overview

• Status: Completed
• Conditions: Thinness; Leanness
• Intervention / Treatment: Other: blood or saliva specimen

• Study Type: Observational
• Enrollment (Actual): 210

Contacts and Locations

Study Locations

• France
  • Saint-Etienne, France, 42055
    • CHU SAINT-ETIENNE

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Fifty families including at least 2 well phenotyped CT index case (grade 2 or 3 of thinness according WHO classification) and members without CT.

Description

Inclusion Criteria:

• For all subjects:

  • age > 18 yrs
  • affiliation to health insurance
  • member of a family including at least 2 CT members and overall 3 evaluable members over 2 generations
  • written and signed consent

• For CT subjects :

  • grade 2 or 3 of thinness according WHO classification
  • women, BMI < 17 kg/m² at 20-30 yrs or < 19 for older subjects
  • men, BMI < 18 kg/m² at 20-30 yrs or < 20 for older subjects
  • absence of DSM criteria for anorexia nervosa
  • young women : normal menses and fat mass percentage 15 % ; absence of DSM criteria for anorexia nervosa
  • men : normal testosterone level

• For subjects without CT :

  • women, BMI > 19 kg/m²
  • men, BMI > 20 kg/m²

Exclusion Criteria:

• CT subjects:

  • smoking > 5 cigarettes / day
  • history of emaciating pathologies
  • intense physical activity > 7 hours / week

• For all subjects :

  • refuse of written consent

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
CT subjects; blood or saliva specimen	Other: blood or saliva specimen; blood or saliva specimen is sampled for DNA extraction in CT family's members
subjects without CT; blood or saliva specimen	Other: blood or saliva specimen; blood or saliva specimen is sampled for DNA extraction in CT family's members

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
chromosome regions' abnormalities	The linkage study is performed in order to identify one or several chromosome regions linked the constitutional thinness phenotype by using genome wide scan (GWAS) techniques in CT families members.	day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
genetic markers	Identify within upper mentioned regions more specific genetic markers (mutation/variant) to characterize genes involved in CT phenotype	day 1

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire de Saint Etienne
• Investigators: Principal Investigator: Bruno Estour, MD PhD, CHU SAINT-ETIENNE; Principal Investigator: Bogdan GALUSCA, MD PhD, CHU SAINT-ETIENNE

Study record dates

Study Major Dates

• Study Start (Actual): October 21, 2010
• Primary Completion (Actual): November 11, 2019
• Study Completion (Actual): November 11, 2019

Study Registration Dates

• First Submitted: August 13, 2015
• First Submitted That Met QC Criteria: August 13, 2015
• First Posted (Estimate): August 17, 2015

Study Record Updates

• Last Update Posted (Actual): July 10, 2020
• Last Update Submitted That Met QC Criteria: July 9, 2020
• Last Verified: July 1, 2020

More Information

Terms related to this study

• Keywords: Constitutional Thinness; linkage study; genome wide scan (GWAS)
• Additional Relevant MeSH Terms: Body Weight; Thinness
• Other Study ID Numbers: 0908129; 2010-A00051-38 (Other Identifier: ANSM)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No