Methylation Status of and in Small for Gestational Age Children with and without Catch-up Growth.

Objective: In small for gestational age (SGA) children, catch-up growth could be influenced by methylation of several genes involved in metabolism. Epigenetics may influence the development of metabolic diseases in adulthood. To compare the methylation of leptin (), glucagon-like peptide-2 receptor (), insulin receptor substrate-2 () in SGA patients with and without catch-up growth.

Methods: Observational prospective study of SGA children. Demographical and clinical variables were collected from clinical records and parents’ questionnaire. Methylation status of , and promoters was evaluated in DNA extracted from patient and one parent saliva samples.

Results: Forty-eight SGA patients were included. Twenty-six (54.2%) had catch-up growth phenotype and 22 (45.8%) did not. The median age was 5.2 years [RIC 4.1-6.8] without difference between groups (p=0.306). The catch-up group had increased appetite (42.3% vs 9.1%, p=0.008), family history of dyslipidemia (42.3% vs 27.3%) and diabetes (34.6% vs 22.7%) compared to non-catch-up group. Catch-up patients had significantly larger waist circumference compared to non-catch-up group (median 55 cm [RIC 52-58] versus median 49.5 cm [RIC46-52]; p<0.001). and were methylated in all samples. was methylated in 60% of SGA patients without difference between groups (p=0.520).

Conclusion: There is no association between methylation and catch-up growth among SGA patients. and were methylated in all SGA patients. Gene methylation may be implicated in metabolic disease later in life. More studies should be performed to confirm this hypothesis.