Dietary folate status appears to influence risk for colorectal cancer possibly by alterations in DNA methylation and nucleotide precursor pools. Polymorphisms (677C-->T and 1298A-->C) in methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, determines enzyme activity. The frequency of polymorphisms in the gene varies extensively in different populations. We sought to determine the association between folate status, folate metabolism, DNA methylation, tobacco, alcohol consumption, and the risk of colorectal adenomas in African Americans. Among 58 patients who underwent a clinically indicated colonoscopy, 23 patients with histology confirmed colorectal polyps and 35 patients without were recruited for a case-control study. Blood samples were collected from fasting patients for determination of serum and red blood cell (RBC) folate, homocysteine, vitamin B(12), and methylation status. Polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) technique was performed to identify the MTHFR 677 C-->T polymorphism and specific PCR was used to analyze adenomatous polyposis coli (APC) gene-promoter sequence methylation. Among 23 cases, 49 polyps (adenomatous, n = 41 and hyperplastic, n= 8) were identified. Twenty-eight (57%) of the polyps were on the left side and 21 (42%) were on the right side of the colon. There was no association between the presence of colon polyps and levels of folate (serum, RBC), vitamin B(12), or homocysteine. Forty-eight individuals (84%) were homozygous for 677 CC. Of these individuals, 18 (37.5%) had >/=1 colorectal polyps, whereas 30 (62.5%) had no polyps. Nine individuals were heterozygous for 677 CT, and 4 (44%) of these individuals had colon polyps. Eighty-eight percent of the APC gene-promoter sequences tested using peripheral blood DNA from patients were unmethylated. Among the individuals who showed APC methylation, 66% had polyps; 33% were polyp free using their blood DNA. There was highly significant association between smoking and alcohol consumption with the presence of a colon polyp (P= .0006 and P= .05, respectively). In conclusion, the lack of the 677 TT may be a significant risk factor for colon neoplasm in the African-American population. Smoking and alcohol consumption were found to be risk factors for colon polyps. APC gene-promoter sequence methylation found in peripheral blood may be an indicator of risk for polyp formation and an important screening tool.

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Classic or large duct primary sclerosing cholangitis (PSC) is part of the PSC spectrum. It is diagnosed on clinical and biochemical findings of cholestasis supported by biliary tree changes on cholangiography, forgoing the need for an invasive liver biopsy. The spectrum contains various PSC variants with distinct clinical courses and outcomes. We present a case of small duct PSC, a rare variant that manifested insidiously with clinical and objective cholestasis but appeared negative on diagnostic cholangiography. Eventually, a liver biopsy was obtained that revealed chronic bilious disease of the small and microscopic ducts with simultaneous changes consistent with liver cirrhosis. Despite presenting like its classical counterpart, small duct PSC can remain undetectable on cholangiography due to the diminutive size of the bile ducts requiring histological confirmation. In contrast to classic PSC, small duct PSC portends a much better prognosis. However, it eventually progresses to the classic form or end-stage liver disease, requiring patients to receive timely surveillance and transplantation referrals. Due to the limited understanding of this disease process, patients with similar presentations often pose a diagnostic dilemma due to the clinical and cholangiographic mismatch. This case aims to reaffirm that a negative cholangiography does not rule out the PSC spectrum and that small duct disease is a rare but growing entity. The paucity in cases emphasizes the importance of isolated reports in guiding workup and management, especially since surveillance schedules and transplantation guidelines have not been formally established.

Central retinal vein occlusion has not been reported previously in patients with sickle cell anemia. We describe the case of a 31-year-old man with sickle cell anemia who developed this complication. The search for risk factors for central retinal vein occlusion in this young patient revealed protein S deficiency and a history of iron deficiency. He was treated with anticoagulation therapy, and his vision improved gradually.

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