Associations of genetically predicted fatty acid levels across the phenome: A mendelian randomisation study.

BACKGROUND: Fatty acids are important dietary factors that have been extensively studied for their implication in health and disease. Evidence from epidemiological studies and randomised controlled trials on their role in cardiovascular, inflammatory, and other diseases remains inconsistent. The objective of this study was to assess whether genetically predicted fatty acid concentrations affect the risk of disease across a wide variety of clinical health outcomes. METHODS AND FINDINGS: The UK Biobank (UKB) is a large study involving over 500,000 participants aged 40 to 69 years at recruitment from 2006 to 2010. We used summary-level data for 117,143 UKB samples (base dataset), to extract genetic associations of fatty acids, and individual-level data for 322,232 UKB participants (target dataset) to conduct our discovery analysis. We studied potentially causal relationships of circulating fatty acids with 845 clinical diagnoses, using mendelian randomisation (MR) approach, within a phenome-wide association study (PheWAS) framework. Regression models in PheWAS were adjusted for sex, age, and the first 10 genetic principal components. External summary statistics were used for replication. When several fatty acids were associated with a health outcome, multivariable MR and MR-Bayesian method averaging (MR-BMA) was applied to disentangle their causal role. Genetic predisposition to higher docosahexaenoic acid (DHA) was associated with cholelithiasis and cholecystitis (odds ratio per mmol/L: 0.76, 95% confidence interval: 0.66 to 0.87). This was supported in replication analysis (FinnGen study) and by the genetically predicted omega-3 fatty acids analyses. Genetically predicted linoleic acid (LA), omega-6, polyunsaturated fatty acids (PUFAs), and total fatty acids (total FAs) showed positive associations with cardiovascular outcomes with support from replication analysis. Finally, higher genetically predicted levels of DHA (0.83, 0.73 to 0.95) and omega-3 (0.83, 0.75 to 0.92) were found to have a protective effect on obesity, which was supported using body mass index (BMI) in the GIANT consortium as replication analysis. Multivariable MR analysis suggested a direct detrimental effect of LA (1.64, 1.07 to 2.50) and omega-6 fatty acids (1.81, 1.06 to 3.09) on coronary heart disease (CHD). MR-BMA prioritised LA and omega-6 fatty acids as the top risk factors for CHD. Although we present a range of sensitivity analyses to the address MR assumptions, horizontal pleiotropy may still bias the reported associations and further evaluation in clinical trials is needed. CONCLUSIONS: Our study suggests potentially protective effects of circulating DHA and omega-3 concentrations on cholelithiasis and cholecystitis and on obesity, highlighting the need to further assess them as prevention treatments in clinical trials. Moreover, our findings do not support the supplementation of unsaturated fatty acids for cardiovascular disease prevention.

[Multiple enterolithiasis, coexisting with bladder and gallbladder lithiasis, associated with colon adenocarcinoma]. / Enterolitiasis múltiple, coexistiendo con litiasis biliar y vesical, asociada a adenocarcinoma de colon.

Enteroliths are calculi primarily formed in the intestine. Enterolithiasis is a rare condition frequently associated with intestinal stasis. Usually it causes no symptoms in most cases, but it can be an important diagnostic clue in patients presenting intestinal occlusive symptoms. We report a case of multiple enterolithiasis, very infrequent pathology, coexisting with bladder and gall bladder lithiasis in a patient with colon adenocarcinoma. Diagnosis was made by X-rays and CT images. Calculi were analysed by several methods: chemical, infrared spectroscopy, stereoscopic microscopy and atomic emission spectroscopy; they showed that caluli are made up of organic material and whilokita (calcium and magnesium ortophosphate). No risk factors for lithogenesis were found in this patient excluding the intestinal stasis caused by intestinal narrowing as a result of adenocarcinoma. Genetic factors are suggested as main contributors to hyperlithogenesis observed in this patient. The physiopathological conditions were studied in depth and literature about this subject reviewed.

[Effects of Shengqing Capsules on cholelithiasis-related genes in guinea pigs].

OBJECTIVE: To explore the molecular mechanisms of Shengqing Capsules in treating cholelithiasis. METHODS: Sixty female guinea pigs were randomized into 3 groups: group I (fed with normal diet), group II (fed with low-protein diet) and group III (fed with low-protein diet and Shengqing Capsules). After six-week feeding, the gallstone formation and the expressions of bilirubin UDP-glucuronosyltransferase (B-UGT) mRNA and cholesterol 7alpha-hydroxylase (CYP7A1) mRNA were observed. RESULTS: The proportions of stone-formed in groups I, II and III were 2/14, 9/12 and 4/14, respectively. There were significant differences among the three groups (P<0.05). The expressions of B-UGT and CYP7A1 mRNAs were higher in both group I and group III as compared with those in the group II (P<0.05). CONCLUSION: Shengqing Capsules can reduce the rate of stone-formation, which may be due to its interference of metabolism of bilirubin and cholesterol and up-regulation of the expressions of B-UGT and CYP7A1 mRNAs.

Clinical and laboratory manifestations of congenital dyserythropoietic anemia type I in young adults.

OBJECTIVES: Congenital dyserythropoietic anemia (CDA) type I is a rare autosomal recessive macrocytic anemia whose natural history is not well documented. The aim of the present study was to evaluate the clinical picture of the disease in young adults. METHODS: The study sample consisted of 17 patients of mean age 11.9 +/- 5.4 yr (range 18-33 yr) and one older patient (age 44 yr), all Israeli Bedouins. The degree of anemia was evaluated as well as the extent of development of gallstones and iron overload. In each subject we determined the hemochromatosis gene mutations and the uridine dyphosphate-glucoronosyltransferase (UGT-1A) gene polymorphism associated with Gilbert's syndrome. RESULTS: The patients were found to have moderate anemia, with the women displaying lower mean hemoglobin levels than the men (8.2 +/- 0.9 g dL(-1) vs. 10 +/- 1.3 g dL(-1); P=0.0059). The majority of patients (59%) had received at least one blood transfusion, with the women having a significantly higher transfusion requirement. Although delayed puberty was noted, final height and weight were within normal limits, and eight patients had progeny. Biliary stones were found in three of 16 patients, two of whom were homozygous for UGT-1A gene polymorphism. None of the patients carried the common hemochromatosis gene mutation, although serum ferritin levels were moderately elevated (788 +/- 332 ng mL(-1)). CONCLUSIONS: CDA type I in young adults is characterized by moderate macrocytic anemia, more severe in women, and a tendency to cholelithiasis and secondary progressive iron overload. We suggest that iron overload in this patient population should be monitored and chelation therapy initiated when indicated to prevent organ damage

Abnormal processing of the human cholecystokinin receptor gene in association with gallstones and obesity.

BACKGROUND & AIMS: Cholesterol gallstone disease and obesity are often associated and share the potential, yet unreported, common etiology of cholecystokinin (CCK) dysfunction. While cloning the human CCK-A receptor complementary DNA (cDNA), we found predominance of a 262-base pair coding region deletion in a cDNA library prepared from a patient with this phenotype. The aim of this study was to determine the abundance, functional significance, and mechanism for generating this gene product. METHODS: Relative abundance of CCK receptor gene products was determined using polymerase chain reaction and hybridization analysis. Constructs were expressed in COS cells and studied for radioligand binding and intracellular calcium responses. A human genomic clone for this receptor was sequenced, and the critical regions were compared with those of the patient. RESULTS: Ninety-three percent of the patient's CCK receptor transcripts contained the 262-base pair deletion, whereas only 1.5% +/- 0.9% of control patients had the deletion. This encoded a receptor that did not bind or signal. The deletion corresponded with the third exon; however, this sequence and flanking introns were normal in the patient. CONCLUSIONS: Abnormality of processing an apparently normal CCK receptor gene yields the predominant product with an absent third exon and encoding a nonfunctional receptor, probably reflecting a defective trans-acting splicing factor. An atypical lariat region in the third intron may explain the presence of small amounts of this product in control patients.