Leanness, Thinness
Conditions
Keywords
Constitutional Thinness, linkage study, genome wide scan (GWAS)
Brief summary
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.
Interventions
OTHERblood or saliva specimen
blood or saliva specimen is sampled for DNA extraction in CT family's members
Sponsors
Centre Hospitalier Universitaire de Saint Etienne
Study design
Observational model
FAMILY_BASED
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| chromosome regions' abnormalities | day 1 | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| genetic markers | day 1 | Identify within upper mentioned regions more specific genetic markers (mutation/variant) to characterize genes involved in CT phenotype |
Countries
France
Outcome results
None listed