Obesity is a serious health problem, that progressively affects individuals' lives with comorbidities involving heart disease, stroke, and diabetes mellitus. Since its prevalence increases particularly in children under age-of-five years, its genetic and environmental causes should be determined for prevention and control of the disease. This study aimed to detect underlying genetic risk factors in a family with an exclusively breastfed obese infant.A three-generation family was recruited to be evaluated for obesity. Detailed examinations along with body mass indexcalculations were performed on available family members. Whole exome sequencing was performed on 7-month-oldobese infant utilizing Illumina-NextSeq550. Bioinformatic analyses were performed on the Genomize SEQ platform with variant filtering at minor allele frequencies (MAF)