Association between methylenetetrahydrofolate reductase polymorphisms, alcohol intake and oropharyngolaryngeal carcinoma in northern Italy

Folate metabolism dysregulation may lead to abnormal cell proliferation and predispose to carcinogenesis by inducing DNA hypomethylation. Folate pathways may be modified by polymorphisms in relevant genes, such as that for methylenetetrahydrofolate reductase (MTHFR), or by alcohol consumption. We investigated the relationship between MTHFR mutations at nucleotides C677T and A1298C, which cause reduced MTHFR enzyme activity, and susceptibility to oropharyngolaryngeal carcinoma in 65 patients and 100 controls. We isolated DNA from peripheral blood leukocytes. In oropharyngolaryngeal carcinoma cases the C677T heterozygous genotype was more frequent (p = 0.018), the allele frequency of MTHFR 677T was greater (p = 0.019) and the genotype 677TT/1298AA was more frequent (p = 0.001). A higher risk of carcinoma was found in the case of moderate drinkers with mutant MTHFR homozygosis or double heterozygosis (OR = 21.2 and OR = 9.1, respectively; p trend = 0.002), and the association was maintained for the different cancer sites (glottic, supraglottic, oropharyngeal). Our findings support the hypothesis that the interaction of alcohol intake and MTHFR polymorphisms might contribute to susceptibility to carcinogenesis of the oropharyngolaryngeal tract

Methylenetetrahydrofolate reductase gene mutations as risk factors for sudden hearing loss

Sudden hearing loss (SHL) can be caused by vascular disorders favoring impaired cochlear perfusion. Several inherited prothrombotic risk factors have been considered in the pathogenesis of vascular impairment, and the possible role of genetic alterations has recently been suggested. Methylenetetrahydrofolate reductase (MTHFR) gene mutations at nucleotides 677 and 1298 cause reduced MTHFR enzyme activity, which leads to increased homocysteine and reduced serum folate levels that are known to be involved in vascular impairment. We studied the relationship between SHL and MTHFR C677T and A1298C gene polymorphisms in 67 patients with SHL and 134 controls. Wild-type MTHFR CC677/AA1298 was significantly more frequent in the controls (P = .05), and gene mutations were significantly more frequent in the patients (P = .001; P = .001 for trend). Fifty-three patients (79.1%) and 56 controls (41.8%) (P = .012) had a double mutation (homozygosis 677TT or 1298CC; compound heterozygosis for both polymorphisms). Homocysteine levels were significantly higher and serum folate levels significantly lower in the patients than in the controls (P < .0001). These data suggest that MTHFR gene polymorphisms may be involved in the pathogenesis of SHL

The etiology of acute hepatitis in Zimbabwe.

bstract The cause of acute viral hepatitis in 141 patients admitted to both Infectious Diseases Hospitals in Harare (Zimbabwe) was hepatitis A in 44, hepatitis B in 86 and hepatitis Non-A Non-B in 11. The wide distribution of hepatitis A and B viruses and early exposure to both in Zimbabwe are shown by the high positivity rate for anti-HAV antibody in patients under 10 years old (87.5%) and for anti-HBs antibody in patients over 20 (60%). Among the 86 hepatitis B cases, e and delta systems were also investigated: 66 patients (76.5%) were HBeAg positive, six (7%) anti-HBe positive and 14 (16.5%) negative for both; only one was anti-delta positive. Two cases of fulminant liver failure (both occurring in HBsAg and anti-HBc IgM positive, but delta-markers negative patients) and five cases of hepatoma (only one of whom was negative for all HBV markers) are described