HLA-linked genes are relevant to celiac disease (CD); the potential genetic differences present worldwide are not fully understood. Previous results suggest that the distribution of HLA-DQ2/DQ7/DQ8 in Chile may differ from that in Europe and North America. In celiac patients and their first-degree relatives (FDRS), we assessed their clinical, serological and histological characteristics, determined HLA-DQ2, HLA-DQ7 and HLA-DQ8 alleles and genotypes, and evaluated the relations between them. A total of 222 individuals were assessed (56 cases, 166 FDRs). 16.9% of FDRs were tTG positive; 53.6% of them showed overweight/obesity and 3% undernourishment; they spontaneously declared being asymptomatic, but detailed questioning revealed that 60.7% experienced symptoms, which had not been investigated. DQ2 was present in 53.9% and 43.9.0% of cases and FDRs (p < 0.05). The most frequent genotype distribution was DQ2/DQ7 (fr 0.392 (cases) and 0.248 (FDRs), respectively, p < 0.02). The next most common genotypes were HLA-DQ2/DQ8 (fr 0.236 in FDRs and 0.176 in cases, p < 0.05). 3.92% cases were not HLA-DQ2/DQ8 carriers. Among tTG positive FDRs, 57.4%, 22.3% and 20.2% carried DQ2, DQ7 and DQ8, respectively. In cases, 72.7% of the biopsies classified Marsh ≥3 carried at least one DQ2; 91.7% of DQ2/DQ2 and 88.3% of DQ2/DQ7 were Marsh ≥3. Thus, DQ2 frequency is lower than reported; the higher frequency found for DQ8 and DQ7 concur with recent publications from Argentine and Brazil. These results suggest that although CD may manifest clinically in ways similar to those described in other populations, some genetic peculiarities in this region deserve further study.

Irritable bowel syndrome (IBS) and vitamin D deficiency are common among children in Latin America. Previous studies show that Bifidobacterium longum35624^TM improves IBS symptoms in adults. This real-world, single-arm, open-label study conducted in Chile investigated the effects of B. longum 35624 (1 × 10⁹ colony-forming units, 12 weeks) on gastrointestinal symptoms (adapted IBS severity scoring system [IBS-SSS]; adapted Questionnaire on Pediatric Gastrointestinal Symptoms [QPGS], and Bristol Stool Form Scale) in 64 children and adolescents (8–18 years) and explored the relationship with baseline vitamin D status. Improvements in all IBS-SSS domains and composite score were observed at week 6 and 12 (p < 0.0007 versus baseline), with 98.3% of participants experiencing numerical improvements in ≥3 domains. Clinically meaningful improvement was seen in 96.6% of participants. The distribution of IBS-SSS severity categories shifted from moderate/severe at baseline to mild/remission (p < 0.0001). Improvements were not maintained during the two-week washout. Low baseline serum vitamin D levels did not correlate to IBS severity or probiotic response. QPGS significantly decreased from baseline to week 6 (p = 0.0005) and 12 (p = 0.02). B. longum 35624 may improve IBS symptoms in children and adolescents, even those with vitamin D deficiency. A confirmatory randomized controlled trial and further exploration of probiotic response and vitamin D status are needed.