A Novel Homozygous Frameshift Mutation in Exon 2 of LEP Gene Associated with Severe Obesity: A Case Report

Background: Monogenic obesity is a rare type of obesity caused by a mutation in a single gene. Patients with monogenic obesity may develop early onset of obesity and severe metabolic abnormalities. Case presentation: A two-and-half-year-old girl was presented to our clinic because of excessive weight gain and hyperphagia. She was born at full term, by normal vaginal delivery with birth weight of 2.82 kg and no complications during pregnancy. The patient was the second child of two healthy, non-obese Saudis with known consanguinity. She gained weight rapidly leading to obesity at the age of three months. Methods: The demographic data and clinical features were recorded. Blood samples were collected and tested for endocrine and metabolic characteristics and genetic studies. Mutations of the LEP gene were screened. The coding exons 2 and 3 and the corresponding exon–intron boundaries were amplified by polymerase chain reaction using specific primers, analyzed by direct sequencing using an ABI sequencer 3500 xL GA (Applied Biosystems), and evaluated using the JSI SeqPilot software. The resulting sequence data were compared with the reference MM_0002302. Conclusion: We report a novel homozygous frameshift mutation c.144delin TAC (G1n49Thrfs*23) in exon 2 of the LEP gene associated with extreme obesity.