DNA repair gene XPD Asp312Asn and XRCC4 G-1394T polymorphisms and the risk of autism spectrum disorder.

Autism spectrum disorder (ASD) is a complex disorder, and its extreme heterogeneity further complicates our understanding of its biology. Epidemiological evidence from family and twin studies supports a strong genetic component in ASD etiology. Oxidative stress and abnormal DNA methylation have been implicated in the pathophysiology of ASD. Brain tissues from ASD cases showed higher levels of oxidative stress biomarkers than healthy controls in postmortem analysis. Association between oxidative stress and DNA damage has been well-known. Thus, we sought to investigate a potential link between DNA repair genes and ASD and analyze the role of XPD Asp312Asn and XRCC4 G-1394T gene polymorphisms for ASD in the Turkish population. Genotyping was conducted by PCR-RFLP based on 100 patients and 96 unrelated healthy controls. We, for the first time, demonstrated a positive association between XRCC4 gene variants and ASD risk. Frequencies of XRCC4-1394 T/G+G/G genotypes were higher in patients (%34) than the controls (%18.7). The statistical analysis revealed that the individuals who had XRCC4-1394 T/G+G/G genotype had an increased risk for ASD (OR = 2.23, 95% CI = 1.10-4.55). However, no significant association was found for XPD Asp312Asn polymorphism with the risk of ASD. Our findings suggest that XRCC4 G-1394T polymorphism might be associated with ASD pathogenesis.

Common MEFV mutations and polymorphisms in an elderly population: an association with E148Q polymorphism and rheumatoid factor levels.

OBJECTIVES: To analyse the most common MEFV (Mediterranean fever gene) mutations and polymorphisms in an elderly population free of chronic inflammatory disease (n=164), and explore possible associations between hsCRP (high sensitive C-reactive protein) and RF (rheumatoid factor) levels with MEFV mutations and polymorphisms. METHODS: An elderly group free of chronic inflammatory disease was chosen among the outpatients of the division of geriatric medicine. Total genomic DNA was isolated from blood, and PCR-RFLP analysis was performed using established protocols. Sera were analyzed for hsCRP and RF levels. RESULTS: The frequencies for 694V (1.8%), 694I (1.8%), 680I (0.6%), 726A (2.1%) and 148Q (5%) alleles were found to be similar to Turkish historic controls, with a carrier frequency of 1/4. Further analyses with rheumatoid factor (RF) levels and mutations revealed a significant association between the presence of the E148Q polymorphism with increased RF levels (>15 mg/dl) (xi2= 7.358, p=0.007, OR=5.41 95% CI 1.41-20.64). CONCLUSIONS: Common MEFV mutations and polymorphisms were similarly represented among the elderly population compared to historic controls. On the other hand, a significant association was found between the presence of E148Q polymorphism and increased RF levels. This suggests that the previously noted increased RF levels in elderly populations may somehow be related to the now described association of RF with MEFV E148Q polymorphism.

The role of Clostridium difficile in childhood nosocomial diarrhea.

The role of Clostridium difficile was investigated in 100 children with nosocomial diarrhea. An etiologic agent was identified in 69 cases, 8 of whom had dual infection. C. difficile-associated diarrhea (Cdad) was defined in 16 children (16%). The mean age of the patients with Cdad was 5.4 y (range 2 months to 13 y) and the male:female ratio was 1.2. All cases with Cdad were on antibiotic therapy. Cdad occurred more frequently in the cases given combined antibiotic treatment than in those given single antibiotic treatment (p < 0.05). One case with neutropenic sepsis died. C. difficile was also investigated in the stool samples of 50 hospitalized children treated with antibiotics who did not develop diarrhea. C. difficile toxins A and B were found in 5 children aged < 2 y in the control group. This study shows that C. difficile is an important cause of nosocomial diarrhea in our hospital population.