From Polymorphisms to Phenotypes: SMAD3 rs17293632 and LTBP3 rs11545200 in Pediatric Inflammatory Bowel Disease.

Background/

Objectives

Early-onset inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), frequently presents with a more severe clinical course. Genetic susceptibility, particularly involving the TGF-β signaling pathway, plays a key role in IBD pathogenesis. SMAD3 and LTBP3 encode crucial components of this pathway and have been implicated in IBD in previous genome-wide association studies.

Methods

This study aimed to assess the clinical significance of the rs17293632 (SMAD3) and rs11545200 (LTBP3) polymorphisms in a pediatric IBD cohort. A total of 286 children (133 with UC and 153 with CD) were recruited from seven pediatric centers in Poland. Clinical data included age at diagnosis, inflammatory markers (CRP, albumin), growth indices (Z-scores for weight, height, and BMI), and treatment regimens.

Results

The LTBP3 rs11545200 minor allele was significantly associated with a younger age at diagnosis, poorer nutritional status during disease flares, and a more frequent use of infliximab-particularly in patients with UC. In CD, the SMAD3 rs17293632 major homozygous genotype was associated with increased use of systemic corticosteroids, suggesting a more severe or treatment-resistant disease phenotype.

Conclusions

The assessed polymorphisms in LTBP3 and SMAD3, both involved in TGF-β signaling, are associated with clinical characteristics of pediatric IBD. These findings support the potential role of genetic variants as biomarkers for disease severity and treatment tailoring, contributing to the development of personalised therapeutic strategies in children with IBD.