The objective of this study is to estimate the proportion of the recurrent deletion Δ6-8 of the LEPR gene in the homozygous and heterozygous state in pediatric cases with severe and early ( before the age of 6) obesity (BMI ≥ IOTF-30) on Reunion Island.

The study of the deletion Δ6-8 of the LEPR gene starts with a saliva sample using a swab in children aged between 3 to 18 years old.

The DNA from this sample will then be analyzed by the PCR technique. If the deletion of the LEPR gene is confirmed in the patient, his adult family members will also be screened using the same procedure.

Inclusion Criteria:

• patient with early severe and non syndromic obesity (BMI> IOTC-30) (before 6 years old)
• adult family members with deletion of LEPR gene
• informed consent form signed by participants or parents
• affiliation to social security scheme

Exclusion Criteria:

• patient with syndromic obesity
• patient Under guardianship or Under judicial protection

Children between 3 to 18 years old with severe obesity (BMI>30) and adult family members.