Fatal gastrointestinal obstruction and hypertension in mice lacking nitric oxide-sensitive guanylyl cyclase

The signaling molecule nitric oxide (NO), first described as endothelium-derived relaxing factor (EDRF), acts as physiological activator of NO-sensitive guanylyl cyclase (NO-GC) in the cardiovascular, gastrointestinal, and nervous systems. Besides NO-GC, other NO targets have been proposed; however, their particular contribution still remains unclear. Here, we generated mice deficient for the beta1 subunit of NO-GC, which resulted in complete loss of the enzyme. GC-KO mice have a life span of 3-4 weeks but then die because of intestinal dysmotility; however, they can be rescued by feeding them a fiber-free diet. Apparently, NO-GC is absolutely vital for the maintenance of normal peristalsis of the gut. GC-KO mice show a pronounced increase in blood pressure, underlining the importance of NO in the regulation of smooth muscle tone in vivo. The lack of an NO effect on aortic relaxation and platelet aggregation confirms NO-GC as the only NO target regulating these two functions, excluding cGMP-independent mechanisms. Our knockout model completely disrupts the NO/cGMP signaling cascade and provides evidence for the unique role of NO-GC as NO receptor.

Desmoid disease in patients with familial adenomatous polyposis

PURPOSE

The aim of this retrospective study was to review the clinical features, and surgical and medical management of patients with familial adenomatous polyposis-associated desmoid tumors.

METHODS

From 1980 to 1997, 97 of 780 patients with familial adenomatous polyposis developed desmoid disease. Clinical and demographic data; operative notes; and histologic, radiologic, and follow-up reports were retrieved from patients' medical records. Risk factors for desmoid disease, such as prior surgery, age at desmoid tumor diagnosis, pregnancy, and family history were sought. The outcome after noncytotoxic and cytotoxic therapy was evaluated with respect to improvement of symptoms.

RESULTS

There were 38 males with a mean age of 32.1 years and 59 females with a mean age of 29.1 years. A family history of desmoid tumors was found in 41 patients (42 percent), and a history of pregnancy was documented in 33 females (56 percent). The most common clinical presentation was small-bowel obstruction (58 percent). One-half of the desmoids were located in the mesentery, and 32 percent were located in the mesentery and the abdominal wall. Desmoids developed after colectomy in 77 cases (80 percent), after a mean time of 4.6 years. Partial resection of desmoid tumor was performed in 46 patients (47 percent), resection of extra-abdominal desmoid tumors was performed in 17 cases (17 percent), and biopsy only was performed in 34 patients (35 percent). Postoperative morbidity was 23 percent after desmoid tumor resection. Eight patients (8 percent) died of their intra-abdominal desmoid. Mean follow-up time was 5.3 years. Sulindac, tamoxifen, or toremifene therapy was able to alleviate symptoms in only 4 of 31 patients. Symptomatic improvement was noted after chemotherapy in six of ten patients with extremely complex desmoids.

CONCLUSION

Desmoid disease was found in 12.4 percent of our patients with familial adenomatous polyposis. In view of the high rate of morbidity, indication for surgery should be limited mainly to acute or chronic small-bowel obstruction, because resection triggers a high recurrence rate. Noncytotoxic therapy was not effective for progressive desmoid tumors, whereas chemotherapy was effective in aggressive cases of intra-abdominal desmoid tumors.

Relative contribution of genetic and nongenetic modifiers to intestinal obstruction in cystic fibrosis

BACKGROUND & AIMS

Neonatal intestinal obstruction (meconium ileus [MI]) occurs in 15% of patients with cystic fibrosis (CF). Our aim was to determine the relative contribution of genetic and nongenetic modifiers to the development of this major complication of CF.

METHODS

A total of 65 monozygous twin pairs, 23 dizygous twin/triplet sets, and 349 sets of siblings with CF were analyzed for MI status, significant covariates, and genome-wide linkage.

RESULTS

Specific mutations in the CF transmembrane conductance regulator (CFTR), the gene responsible for CF, correlated with MI, indicating a role for CFTR genotype. Monozygous twins showed substantially greater concordance for MI than dizygous twins and siblings (P = 1 x 10(-5)), showing that modifier genes independent of CFTR contribute substantially to this trait. Regression analysis revealed that MI was correlated with distal intestinal obstruction syndrome (P = 8 x 10(-4)). Unlike MI, concordance analysis indicated that the risk for development of distal intestinal obstruction syndrome in CF patients is caused primarily by nongenetic factors. Regions of suggestive linkage (logarithm of the odds of linkage >2.0) for modifier genes that cause MI (chromosomes 4q35.1, 8p23.1, and 11q25) or protect from MI (chromosomes 20p11.22 and 21q22.3) were identified by genome-wide analyses. These analyses did not support the existence of a major modifier gene on chromosome 19 in a region previously linked to MI.

CONCLUSIONS

The CFTR gene along with 2 or more modifier genes are the major determinants of intestinal obstruction in newborn CF patients, whereas intestinal obstruction in older CF patients is caused primarily by nongenetic factors.

Distal intestinal obstruction syndrome in adults with cystic fibrosis

BACKGROUND & AIMS

With the improved survival of patients with cystic fibrosis (CF), gastrointestinal complications become more evident in adults with this condition. The aims of this study were to determine the prevalence and clinical features of distal intestinal obstruction syndrome (DIOS) and its relationship with the cystic fibrosis transmembrane conductance regulator (CFTR) genotype in an adult CF population.

METHODS

Cross-sectional study was conducted in an adult CF cohort.

RESULTS

Among 171 adults with CF (mean age, 28.9 years), 27 patients (15.8%) reported 43 episodes of DIOS. No significant association was found between DIOS and a history of meconium ileus. The first episode of DIOS occurred in adulthood in 21 cases (77.8%). DIOS recurred in 13 patients (48.1%). All patients who developed DIOS had pancreatic insufficiency. Pulmonary function was significantly more altered in patients with DIOS than in the other patients, but pancreatic insufficiency and age might act as confounding factors. DIOS occurred in 21.9% of patients with a severe CFTR genotype and in only 2.4% of patients with a mild CFTR genotype (P < 0.005).

CONCLUSIONS

DIOS is frequent in adults with CF with a severe CFTR genotype and/or advanced-stage pulmonary disease. The relative contributions of malabsorption and impaired intestinal secretion in the development of DIOS are discussed.

Increased expression of the chemokine fractalkine in Crohn's disease and association of the fractalkine receptor T280M polymorphism with a fibrostenosing disease Phenotype

BACKGROUND

The fractalkine receptor CX3CR1 has been shown to be involved in inflammation and immune response. Recently, two polymorphisms of CX3CR1 (V249I and T280M) were reported.

AIMS

Our aim was to analyze fractalkine expression and the role of CX3CR1 polymorphisms in Crohn's disease (CD).

METHODS

We determined fractalkine mRNA expression in the intestinal epithelial cell (IEC) line SW480 after stimulation with proinflammatory cytokines as well as in inflamed (n = 14) and noninflamed (n = 14) CD lesions by quantitative PCR. By restriction fragment length polymorphism analysis, genomic DNA from 206 patients with CD and 211 unrelated controls was analyzed for the two single nucleotide polymorphisms in the CX3CR1 gene, which result in the V249I and T280M substitutions.

RESULTS

All proinflammatory stimuli (TNF-alpha, IL-1beta, LPS) significantly increased fractalkine mRNA expression in IEC. There was also a significant increase in fractalkine mRNA expression in inflamed lesions of CD patients when compared to noninflamed colonic mucosa (p = 0.02). Intestinal fractalkine mRNA levels correlated highly with IL-8 mRNA expression levels (r = 0.931). However, there was no difference in the V249I and T280M genotype frequencies between CD patients and the control group. In the CD group, 33.0% were heterozygous and 8.3% homozygous for the V249I polymorphism, while 23.3% were heterozygous and 4.4% homozygous for the T280M polymorphism. All T280M homozygotes were diagnosed of intestinal stenosis (p = 0.03 vs wildtype and heterozygous carriers) and had significantly more often ileocolonic involvement more often than patients with wildtype and heterozygous genotypes (p = 0.01). These associations were independent of the CARD15 genotype status.

CONCLUSIONS

The expression of the chemokine fractalkine is upregulated by proinflammatory cytokines and enhanced in inflamed CD lesions. The CX3CR1 T280M polymorphism appears to influence CD phenotype and localization.

A familial visceral myopathy

A kindred contained at least 18 members with visceral myopathy. Sixteen had symptoms of chronic obstruction of the gastrointestinal or urinary tracts. Of six patients with megaduodenum on contrast roentgenograms, two were asymptomatic. Four patients had redundant colon on barium enema, and four had megacystis. Specimens from duodenum, jejunum, ileum, colon, or urinary bladder from five patients showed thinning and extensive collagen replacement of the longitudinal muscle layer; ganglion cells were normal by light and electron microscopy. Esophageal manometry in three patients showed decreased gastroesophageal sphincter pressures and no contractions in the smooth muscle segment of the esophagus; duodenal manometry showed a low frequency and amplitude of contractions. Three patients developed fever and signs of peritonitis after operations to bypass dilated segments. This seems to be a generalized smooth muscle disease with variable clinical manifestations and with an autosomal dominant or sex-linked dominant mode of inheritance.

Predictive value of the CARD15 variant 1007fs for the diagnosis of intestinal stenoses and the need for surgery in Crohn's disease in clinical practice: results of a prospective study

BACKGROUND AND AIM

The diagnostic and therapeutic relevance of CARD15 genotyping in Crohn's disease (CD) for daily clinical practice has not been investigated so far. We therefore analyzed whether CARD15 variants are independent predictive factors for small bowel stenosis in CD evaluated by magnetic resonance enteroclysis (MRE). On the basis of these findings, the potential implications for patient management were investigated.

METHODS

Eighty CD patients with clinical symptoms suggestive of small bowel stenosis were included. All patients were genotyped for the CARD15 variants c.2104C > T (p.R702W), c.2722G > C (p.G908R), and c.3019_3020insC (p.Leu1007fsX1008) and examined by MRE of the small bowel.

RESULTS

CARD15 variants were found in 40 (50%) patients. MRE identified 31 (38%) patients with small bowel stenoses. Twenty-five of the 40 (62%) patients with at least one CARD15 variant were diagnosed of intestinal stenosis by MRE (odds ratio [OR] = 9.44; confidence interval [CI] 3.21-27.77; P = 0.00028, Bonferroni corrected). Particularly, the presence of the 1007fs variant was associated with an increased risk of an intestinal stenosis (OR = 12.00, CI 3.47-41.54, P = 0.00042, Bonferroni corrected). Twenty-one of 31 (68%) patients with stenoses required surgical intervention, with 13 of these 21 (62%) patients carrying the 1007fs variant.

CONCLUSION

In the largest prospective study analyzing the diagnostic value of CARD15 variants in CD patients performed so far, we identified the 1007fs variant as strong predictor for intestinal stenoses with need for surgery in CD patients. Genotyping could therefore be an important diagnostic tool in clinical practice for identifying high-risk patients with specific diagnostic and therapeutic needs. Moreover, MRE is an excellent technique for diagnosing small bowel stenoses.

Chronic idiopathic intestinal pseudo-obstruction syndrome in children--clinical characteristics and prognosis

Eleven children with the diagnosis of chronic idiopathic intestinal pseudo-obstruction are presented. Four children, all siblings of a symptomatic patient, were asymptomatic and were diagnosed radiographically. The clinical course was characterized by intermittent episodes of abdominal distention, vomiting, abdominal pain, diarrhea, constipation, and malnutrition. Radiographic studies were most helpful in making the diagnosis. Findings on upper gastrointestinal series included abnormal esophageal motility, delayed gastric emptying, dilated loops of small bowel, and disorganized transit of barium. Half of the patients had abnormal evacuation patterns on barium enema. Manometric studies of esophageal motility were abnormal in seven of ten children. In those patients studied, small bowel and rectal biopsies contained ganglion cells. Treatment was directed at relieving symptoms, which in four patients became persistent and required total parenteral nutrition. CIIPS carries a poor long-term prognosis in children.

The C. elegans lethal gut-obstructed gob-1 gene is trehalose-6-phosphate phosphatase

We identified the gob-1 (gut-obstructed) gene in a forward genetic screen for intestinal defects in the nematode Caenorhabditis elegans. gob-1 loss of function results in early larval lethality, at least in part because of a blocked intestinal lumen and consequent starvation. The gob-1 gene is first expressed in the 8E cell stage of the embryonic intestine, and the GATA factor ELT-2 is sufficient but not necessary for this early phase of gob-1 expression; gob-1 expression later becomes widespread in embryos, larvae, and adults. GOB-1 is a member of the HAD-like hydrolase superfamily and shows a robust and specific phosphatase activity for the substrate trehalose-6-phosphate. Trehalose is a glucose disaccharide found in bacteria, fungi, plants, insects, and nematodes but not in mammals. Trehalose plays a number of critical roles such as providing flexible energy reserves and contributing to thermal and osmotic stress resistance. In budding yeast and in plants, the intermediate in trehalose synthesis, trehalose-6-phosphate, has additional critical but less well-defined roles in controlling glycolysis and carbohydrate metabolism. Strong loss-of-function mutants in the C. elegans tps-1 and tps-2 genes (which encode the two trehalose phosphate synthases responsible for trehalose-6-phosphate synthesis) completely suppress the lethality associated with gob-1 loss of function. The suppression of gob-1 lethality by ablation of TPS-1 and TPS-2, the upstream enzymes in the trehalose synthesis pathway, suggests that gob-1 lethality results from a toxic build-up of the intermediate trehalose-6-phosphate, not from an absence of trehalose. GOB-1 is the first trehalose-6-phosphate phosphatase to be identified in nematodes and, because of its associated lethality and distinctive sequence properties, provides a new and attractive target for anti-parasitic drugs.

Functional intestinal obstruction due to deficiency of argyrophil neurones in the myenteric plexus. Familial syndrome presenting with short small bowel, malrotation, and pyloric hypertrophy

In 3 infants functional intestinal obstruction, associated with a short small intestine, malrotation, and pyloric hypertrophy, was shown to be due to failure of development of the argyrophil myenteric plexus, with the absence of ongoing peristalsis. 4 infants with similar clinical features have been described previously, and there is evidence for an autosomal recessive mode of inheritance of this syndrome.

Gdnf haploinsufficiency causes Hirschsprung-like intestinal obstruction and early-onset lethality in mice

Hirschsprung disease (HSCR) is a common congenital disorder that results in intestinal obstruction and lethality, as a result of defective innervation of the gastrointestinal (GI) tract. Despite its congenital origin, the molecular etiology of HSCR remains elusive for >70% of patients. Although mutations in the c-RET receptor gene are frequently detected in patients with HSCR, mutations in the gene encoding its ligand (glial cell line-derived neurotrophic factor [GDNF]), are rarely found. In an effort to establish a possible link between human HSCR and mutations affecting the Gdnf locus, we studied a large population of mice heterozygous for a Gdnf null mutation. This Gdnf(+/-) mutant cohort recapitulates complex features characteristic of HSCR, including dominant inheritance, incomplete penetrance, and variable severity of symptoms. The lack of one functioning Gdnf allele causes a spectrum of defects in gastrointestinal motility and predisposes the mutant mice to HSCR-like phenotypes. As many as one in five Gdnf(+/-) mutant mice die shortly after birth. Using a transgenic marking strategy, we identified hypoganglionosis of the gastrointestinal tract as a developmental defect that renders the mutant mice susceptible to clinical symptoms of HSCR. Our findings offer a plausible way to link an array of seemingly disparate features characteristic of a complex disease to a much more narrowly defined genetic cause. These findings may have general implications for the genetic analysis of cause and effect in complex human diseases.

Long-term survival of the exon 10 insertional cystic fibrosis mutant mouse is a consequence of low level residual wild-type Cftr gene expression

Recently we have created a mouse model of cystic fibrosis (CF) by insertional gene targeting to exon 10. In common with CF subjects, this model displays a low incidence of meconium ileus. This contrasts strikingly with the very high level of fatal intestinal obstruction in the three other CF mouse models so far described. We investigate here the molecular basis of this difference in phenotype. We show that the partial duplication consequent upon insertional gene targeting allows exon skipping and aberrant splicing to produce normal Cftr mRNA, but at levels greatly reduced compared with wild-type mice. Furthermore, instead of the predicted mutant Cftr transcript, a novel mRNA is produced that utilizes cryptic splice sites in the disrupting plasmid sequence. However, we have previously shown that these mice display the ion transport defect characteristic of CF, and mutant animals can be distinguished from their normal littermates on this basis. Consistent with this, residual CFTR function has recently been observed for several "mild" mutations in CF individuals who display pancreatic sufficiency but still develop lung disease. We conclude that (i) residual wild-type mRNA in the exon 10 insertional mutant mouse ameliorates the severity of the intestinal phenotype observed in the absolute "null" CF mice, (ii) the presence of low-level residual wild-type Cftr mRNA does not correct the CF ion transport defect, and (iii) the long-term survival of this insertional mutant mouse provides the opportunity to address the factors important in development of lung disease.

Chronic intestinal pseudoobstruction in young children

We studied 8 young children (4 boys and 4 girls) with chronic intestinal pseudoobstruction. Intestinal pseudoobstruction, recurrent urinary tract infections, and dysuria occurred between the ages of a few weeks to 5 yr old. All had marked dilatation of the entire gastrointestinal tract distal to the esophagus, and megacystis. Conventional pathologic examinations of the full-thickness specimens of the gastrointestinal tract were normal in 5 and abnormal in 2 patients. The abnormalities included increased fibrosis and lipofuscin pigment in the smooth muscle cells. Myenteric plexus examination, using the Smith's method in 2 patients, was normal. Biopsy specimens from urinary bladders examined in 3 patients revealed separation of individual smooth muscle cells by collagen fibers. Intestinal manometric studies performed in 3 patients showed only weak and infrequent contractions during fasting and after feeding. Severe and extensive dysfunction of the gastrointestinal and urinary tracts with relatively normal histologic appearance are typical for these children.

Genetic differences between cystic fibrosis with and without meconium ileus

41 families with cystic fibrosis, (CF) were tested for restriction fragment length polymorphisms (RFLPs) detected by four DNA probes all of which are tightly linked to the CF gene. 17 of the families had an affected child with, and 24 had one without, meconium ileus. In all cases, CF segregates with these gene probes; however, those with and those without meconium ileus differed in haplotype for CF chromosomes with respect to pJ3.11, which suggests that because of multiallelism (different mutations of the same locus) some CF patients present with meconium ileus and others do not.

Overo lethal white foal syndrome: equine model of aganglionic megacolon (Hirschsprung disease)

The lethal white foal syndrome (LWFS) is a congenital abnormality of overo spotted horses which is a model for human aganglionic megacolon or Hirschsprung disease. Foals with LWFS have an all white, or nearly all white, coat. They also present clinically with an intestinal obstruction that proves fatal within the first few days of life. The LWFS involves both melanocytes and intestinal ganglion cells, and appears to result from a genetic defect involving neural crest cells. This report describes pathologic studies of two recent cases of LWFS. Two different hypothetical models of inheritance of LWFS are presented and discussed.

Familial occurrence of meconium ileus

A recurrence rate for meconium ileus of 39% was found among C.F. affected siblings in a study of 488 families with at least one C.F. child born over a 24 year period. The recurrence rate was highly significant and indicated a familial trend for the occurrence of meconium ileus. The findings of the study support the existence of genetic heterogeneity in cystic fibrosis.

Inherited ophthalmoplegia with intestinal pseudo-obstruction

A new inherited neuromuscular disease was identified in 4 patients (1 male, 3 females), offspring of consanguineous marriages, belonging to the same kindred. The proband was a 24-year-old female with history of ptosis and ophthalmoplegia since childhood and progressive intestinal pseudo-obstruction for the last 4 years of her life. A sural nerve biopsy showed axonal and demyelinating neuropathy. Muscle biopsies of pectoral and gastrocnemius revealed myopathic alterations with marked variation in muscle fiber size, atrophy of both fiber types and normal mitochondria. An upper gastrointestinal study showed barium in the stomach after 8 h and jejunal diverticula. Tests for absorption of fat, protein, carbohydrate, folic acid and vitamin B12 were normal. Serum levels of vitamin A and lipoproteins were also normal. The patient underwent partial gastrectomy and gastrojejunostomy. Postoperatively, she developed severe pancreatitis, sepsis, peritonitis and expired. Tissue samples from the proband and from her brother, revealed normal mucosa, but degeneration of smooth muscle of the stomach and small intestine. The myenteric plexus and vagus nerves were normal. The biochemical studies of contractile proteins (myosin, actin, tropomyosin) in the fresh and cultured smooth muscle cells of the proband obtained at the time of gastrectomy showed a 50-75% decrease in the synthesis of different contractile proteins. Turnover of contractile proteins and synthesis and turnover of collagen showed normal values. The reduction in synthesis of contractile proteins may account for the weak peristalsis and be a factor in the pathogenesis of the intestinal pseudo-obstruction.

Oculogastrointestinal muscular dystrophy

The author reports on four patients (one male, three females) from the same kindred with a newly recognized autosomal recessive condition involving striated and smooth muscle that has been designated oculogastrointestinal muscular dystrophy. It is characterized by ptosis, ophthalmoplegia, and progressive intestinal pseudo-obstruction leading to malnutrition and death before 30 y. Autopsy studies in two cases showed a severe primary myopathy of smooth muscles of the stomach and intestine with intact myenteric plexus and vagus nerves. The proposita notably had myopathic changes of striated muscles but also involvement of the peripheral nerves and central nervous system characterized by demyelinating and axonal neuropathy and focal spongiform degeneration of the posterior columns.

A perspective for pediatric surgeons: chronic idiopathic intestinal pseudoobstruction

Chronic idiopathic intestinal pseudoobstruction (CIIP) is a disorder of alimentary tract motility with onset of symptoms in adolescence or young adulthood, characterized by recurring attacks of abdominal pain, distention, vomiting, and constipation often leading to malnutrition and death. Starting with an adolescent patient, treated for a succession of life-threatening attacks of pseudoobstruction, the authors have identified CIIP in four generations of a Virginia family. Studies show characteristic dilation and diminished motility of the esophagus and intestine. Surgery's role in CIIP is palliative, and operation should only be offered when medical measures have failed to control symptoms.

Evaluation of fetal echogenic bowel in the second trimester

Previous studies cite different possible etiologies for fetal echogenic bowel (FEB). The purpose of this study was to evaluate the possible etiologies for second-trimester FEB, and to provide clinical guidelines for evaluation of this finding. The study included 79 patients diagnosed with FEB in the second trimester. Fifteen cases (19%) were associated with maternal vaginal bleeding. Of these, 12 patients underwent amniocentesis, 9 of which had visible blood products in the amniotic fluid. Seven cases (8.9%) had associated severe malformation. Seven other cases (8.9%) were noted in multifetal pregnancies. Five fetuses (6.3%) had evidence of bowel obstruction or perforation not associated with cystic fibrosis (CF). Chromosomal aberrations were found in 5 fetuses (6.3%). Intrauterine infection with cytomegalovirus, herpes simplex virus, varicella-zoster virus, or parvovirus B-19 was documented in 5 patients (6.3%). Three cases (3.8%) were associated with subsequent unexplained stillbirth. Two fetuses (2.5%) were found to be affected by CF. Finally, in 30 cases (38%), no obvious reason for FEB was found. We conclude that the evaluation of second-trimester FEB should include targeted ultrasound for associated malformations, infectious studies, DNA analysis for CF mutations, amniocentesis for chromosomal analysis and evaluation of the amniotic fluid for degraded blood products, and an autopsy in cases of stillbirth. Even when no apparent reason is found, pregnancies should be considered at high risk for poor outcome.

The V249I polymorphism of the CX3CR1 gene is associated with fibrostenotic disease behavior in patients with Crohn's disease

OBJECTIVES

CX3CR1, the receptor of CX3CL1/fractalkine, is involved in regulation of inflammatory response and the CX3CR1-I249-M280 naturally occurring mutants are associated with altered binding to the ligand. Our aim was to evaluate the frequency of CX3CR1 V249I and T280M polymorphisms and NOD2/CARD15 mutations in Crohn's disease patients and to search for a relationship with phenotype.

METHODS

Clinical data were retrospectively collected. V249I and T280M polymorphisms of CX3CR1 gene and NOD2/CARD15 mutations (R702W, G908R, 3020InsC) were identified.

RESULTS

Two hundred and thirty-nine patients (140 females, 39.7+/-14.1 years) were included. About 37.4% were heterozygous and 8.8% were homozygous for the V249I CX3CR1 polymorphism, 18.1% were heterozygous and 1.3% homozygous for the T280M CX3CR1 polymorphism and 35.9% had at least one of the three mutations of NOD2/CARD15. The T280M CX3CR1 polymorphism was not associated with any phenotype. In univariate analysis, stenosis was significantly associated with both V249I CX3CR1 polymorphism and 3020InsC NOD2/CARD15 mutations. In smoker patients carrying the CX3CR1 allele I249, there was a significant increase in the frequency of fibrostenosing disease [P=0.005, odds ratio (OR): 3.25] whereas this relationship disappeared in the group of nonsmokers (P=0.72). In multivariate analysis, 3020InsC NOD2/CARD15 mutations and the V249I CX3CR1 polymorphism were independent risk factors for intestinal stenosis (P=0.046, OR: 1.8 and P=0.044, OR: 2.4, respectively).

CONCLUSION

In Crohn's disease, V249I CX3CR1 polymorphism is associated with intestinal strictures, particularly in smokers. This association is independent of CARD15 mutations.

Sigmoid volvulus: new thoughts on the epidemiology

Sigmoid volvulus usually affects the elderly, but it is being increasingly described in a younger age group. In these patients the diagnosis is often delayed, due to a prolonged and intermittent history. Three patients, of 31,36, and 67 years, are described here, and they demonstrate an increased incidence within families, which has not been previously recognized. Awareness of this possibility may allow earlier diagnosis when investigating young patients with intermittent abdominal symptoms, whose relatives are known to be affected.