Familial Crohn's disease in single or multiple first-degree relatives

Where Do We Stand in the Behavioral Pathogenesis of Inflammatory Bowel Disease? The Western Dietary Pattern and Microbiota-A Narrative Review

Despite the increasing knowledge with regard to IBD (inflammatory bowel disease), including ulcerative colitis (UC) and Crohn’s disease (CD), the etiology of these conditions is still not fully understood. Apart from immunological, environmental and nutritional factors, which have already been well documented, it is worthwhile to look at the possible impact of genetic factors, as well as the composition of the microbiota in patients suffering from IBD. New technologies in biochemistry allow to obtain information that can add to the current state of knowledge in IBD etiology.

Familial aggregation of inflammatory bowel disease in India: prevalence, risks and impact on disease behavior

Background/Aims

Information about familial aggregation of inflammatory bowel disease (IBD) in Asia is limited. We aimed to analyze the prevalence and risk of familial IBD in an Indian cohort and compare familial and sporadic cases.

Methods

Familial IBD cases were identified from a large prospectively maintained IBD registry. The prevalence of IBD in first- and seconddegree relatives of index cases was evaluated. The disease behavior was compared to that of sporadic cases.

Results

Total 3,553 patients (ulcerative colitis [UC], 2,053; Crohn’s disease [CD], 1,500) were included. Familial IBD was noted in 4.13% of CD and 4.34% of UC patients. Family history was commoner in pediatric group (< 18 years) (P= 0.0002; odds ratio [OR], 2.8; 95% confidence interval [CI], 1.6–4.8). Majority had paternal transmission (UC, 67.42%; CD, 70.97%). Concordance of disease type was higher in UC (79.7%) compared to CD (37.1%). Familial IBD was associated with higher cumulative relapse rate (CD, P< 0.001; UC, P< 0.001), higher cumulative rate of surgery (CD, P< 0.001; UC, P< 0.001) and higher rate of biologic use (CD, P= 0.010; UC, P= 0.015). Pan-colitis was higher in familial UC (P= 0.003; OR, 1.935; 95% CI, 1.248–3.000). Fistulizing disease was commoner in familial CD (P= 0.041; OR, 2.044; 95% CI, 1.030–4.056).

Conclusions

The prevalence of familial IBD in India appears comparable to rest of Asia but lower than the West. It is associated with a younger age of onset, higher incidence of pan-colitis in UC and fistulizing complications in CD. Familial IBD has higher cumulative relapse, surgery and biologic use rates. Hence, family history of IBD could have important prognostic implications.

Investigation of inflammatory bowel disease risk factors in 4 families in central China

The prevalence of inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is increasing markedly in China. The present study performed pedigree analysis of 4 families with a history of IBD and investigated the association of genetic and environmental factors with susceptibility to IBD. A total of 10 IBD patients (8 CD patients and 2 UC patients) and 90 family members were included in the present study. The clinical characteristics of familial subjects were compared with those of patients with sporadic IBD. Previously reported mutations, namely interleukin-10 receptor (IL10R)-A Thr84Ile, IL10RA Gly141Arg, IL10RB Trp159X, X-linked inhibitor of apoptosis (XIAP) Cys203Tyr, nucleotide-binding oligomerization domain-containing protein 2 (NOD2) Arg702Trp, NOD2 Gly908Arg and NOD2 Leu1007fsinsC, were screened in the patients with IBD, and selected demographic factors were compared between the patients and their unaffected family members. It was observed that single-gene and multi-gene inheritance patterns contributed to IBD in Chinese families. Based on data from the registry system, the ratio of patients with a family history of IBD was 1.25%, which was lower than that in the Western population. First-degree relatives were found to be more susceptible to IBD, and siblings were affected more frequently. Furthermore, the median age of diagnosis was younger in familial patients than in sporadic patients (29.0 vs. 36.0 for CD; 35.5 vs. 41.0 for UC). However, none of the 7 susceptibility loci were present in any of the familial patients. Immigration was a significant risk factor of IBD (odds ratio: 4.667; 95% confidence interval: 1.165-18.690; P=0.021). In conclusion, genetic heterogeneity exits between Chinese families with IBD and the Western population. The present findings suggest that genetic background and environmental factors serve a role in the pathogenesis of IBD.

Familial and ethnic risk in inflammatory bowel disease

Familial aggregation in inflammatory bowel disease (IBD) has been established for several decades, reflecting shared genetic and environmental susceptibility. A positive family history remains the strongest recognizable risk factor for the development of IBD and is reported in around 8-12% of IBD patients. Crohn’s disease shows a more frequent familial pattern than ulcerative colitis. The risk of developing IBD in first-degree relatives of an affected proband is increased 4- to 8-fold. The risk for twins and children born from couples who both have IBD is also substantially higher; a cumulative effect of the number of family members affected has been described, with the highest incidence being described for families with three or more affected members. Herein, we review the available evidence regarding familial IBD, and briefly discuss the variation of IBD across different races and ethnicities, hoping to provide a useful update and a practical guide that can serve clinicians as a guide for counseling.

Influence of environmental factors in the development of inflammatory bowel diseases

Idiopathic inflammatory bowel diseases (IBD), Crohn’s disease (CD) and ulcerative colitis (UC), are multifactorial diseases that are manifested after disruption of a genetic predisposed individual and its intestinal microflora through an environmental stimulus. Urbanization and industrialization are associated with IBD. Epidemiological data, clinical observations and family/immigrants studies indicate the significance of environmental influence in the development of IBD. Some environmental factors have a different effect on the subtypes of IBD. Smoking and appendectomy is negatively associated with UC, but they are aggravating factors for CD. A westernized high fat diet, full of refined carbohydrates is strongly associated with the development of IBD, contrary to a high in fruit, vegetables and polyunsaturated fatty acid-3 diet that is protective against these diseases. High intake of nonsteroidal antiinflammatory drug and oral contraceptive pills as well as the inadequacy of vitamin D leads to an increased risk for IBD and a more malignant course of disease. Moreover, other factors such as air pollution, psychological factors, sleep disturbances and exercise influence the development and the course of IBD. Epigenetic mechanism like DNA methylation, histone modification and altered expression of miRNAS could explain the connection between genes and environmental factors in triggering the development of IBD.

Phenotypic concordance in familial inflammatory bowel disease (IBD). Results of a nationwide IBD Spanish database

BACKGROUND & AIMS

Disease outcome has been found to be poorer in familial inflammatory bowel disease (IBD) than in sporadic forms, but assessment of phenotypic concordance in familial IBD provided controversial results. We assessed the concordance for disease type and phenotypic features in IBD families.

METHODS

Patients with familial IBD were identified from the IBD Spanish database ENEIDA. Families in whom at least two members were in the database were selected for concordance analysis (κ index). Concordance for type of IBD [Crohn's disease (CD) vs. ulcerative colitis (UC)], as well as for disease extent, localization and behaviour, perianal disease, extraintestinal manifestations, and indicators of severe disease (i.e., need for immunosuppressors, biological agents, and surgery) for those pairs concordant for IBD type, were analyzed.

RESULTS

798 out of 11,905 IBD patients (7%) in ENEIDA had familial history of IBD. Complete data of 107 families (231 patients and 144 consanguineous pairs) were available for concordance analyses. The youngest members of the pairs were diagnosed with IBD at a significantly younger age (p<0.001) than the oldest ones. Seventy-six percent of pairs matched up for the IBD type (κ=0.58; 95%CI: 0.42-0.73, moderate concordance). There was no relevant concordance for any of the phenotypic items assessed in both diseases.

CONCLUSIONS

Familial IBD is associated with diagnostic anticipation in younger individuals. Familial history does not allow predicting any phenotypic feature other than IBD type.

Exome sequencing identifies DLG1 as a novel gene for potential susceptibility to Crohn's disease in a Chinese family study

BACKGROUND

Genetic variants make some contributions to inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). More than 100 susceptibility loci were identified in Western IBD studies, but susceptibility gene has not been found in Chinese IBD patients till now. Sequencing of individuals with an IBD family history is a powerful approach toward our understanding of the genetics and pathogenesis of IBD. The aim of this study, which focuses on a Han Chinese CD family, is to identify high-risk variants and potentially novel loci using whole exome sequencing technique.

METHODS

Exome sequence data from 4 individuals belonging to a same family were analyzed using bioinformatics methods to narrow down the variants associated with CD. The potential risk genes were further analyzed by genotyping and Sanger sequencing in family members, additional 401 healthy controls (HC), 278 sporadic CD patients, 123 UC cases, a pair of monozygotic CD twins and another Chinese CD family.

RESULTS

From the CD family in which the father and daughter were affected, we identified a novel single nucleotide variant (SNV) c.374T>C (p.I125T) in exon 4 of discs large homolog 1 (DLG1), a gene has been reported to play multiple roles in cell proliferation, T cell polarity and T cell receptor signaling. After genotyping among case and controls, a PLINK analysis showed the variant was of significance (P<0.05). 4 CD patients of the other Chinese family bore another non-synonymous variant c.833G>A (p.R278Q) in exon 9 of DLG1.

CONCLUSIONS

We have discovered novel genetic variants in the coding regions of DLG1 gene, the results support that DLG1 is a novel potential susceptibility gene for CD in Chinese patients.

Natural history and long-term clinical course of Crohn’s disease

Crohn’s disease is a chronic inflammatory disease process involving different sites in the gastrointestinal tract. Occasionally, so-called metastatic disease occurs in extra-intestinal sites. Granulomatous inflammation may be detected in endoscopic biopsies or resected tissues. Genetic, epigenetic and environmental factors appear to play a role. Multiple susceptibility genes have been described in both familial and non-familial forms while the disease is phenotypically heterogeneous with a female predominance. The disorder occurs over a broad age spectrum, from early childhood to late adulthood. More than 80% are diagnosed before age 40 years usually with terminal ileal and colonic involvement. Pediatric-onset disease is more severe and more extensive, usually with a higher chance of upper gastrointestinal tract disease, compared to adult-onset disease. Long-term studies have shown that the disorder may evolve with time into more complex disease with stricture formation and penetrating disease complications (i.e., fistula, abscess). Although prolonged remission may occur, discrete periods of symptomatic disease may re-appear over many decades suggesting recurrence or re-activation of this inflammatory process. Eventual development of a cure will likely depend on identification of an etiologic cause and a fundamental understanding of its pathogenesis. Until now, treatment has focused on removing risk factors, particularly cigarette smoking, and improving symptoms. In clinical trials, clinical remission is largely defined as improved numerical and endoscopic indices for “mucosal healing”. “Deep remission” is a conceptual, more “extended” goal that may or may not alter the long-term natural history of the disease in selected patients, albeit at a significant risk for treatment complications, including serious and unusual opportunistic infections.

Association between toll-like receptors/CD14 gene polymorphisms and inflammatory bowel disease in Korean population

The innate immune response in patients who develop inflammatory bowel disease (IBD) may be abnormal. However, the exact role of Toll-like receptors (TLRs) / CD14 gene in the pathogenesis of IBD has not been fully elucidated. We aimed to investigate the association between polymorphisms of TLR1, 2, 4, 6, and CD14 gene and susceptibility to IBD in Korean population. A total 144 patients of IBD (99 patients with ulcerative colitis, 45 patients with Crohn's disease) and 178 healthy controls were enrolled. Using a PCR-RFLP, we evaluated mutations of TLR1 (Arg80Thr), TLR2 (Arg753Gln and Arg677Trp), TLR4 (Asp299Gly and Thr399Ile), TLR6 (Ser249Pro) genes and the -159 C/T promoter polymorphism of CD14 gene. No TLR polymorphisms were detected in Korean subjects. T allele and TT genotype frequencies of CD14 gene were significantly higher in IBD patients than in healthy controls. In subgroup analysis, T allelic frequency was higher in pancolitis phenotype of ulcerative colitis. In Korean population, the promoter polymorphism at -159 C/T of the CD14 gene is positively associated with IBD, both ulcerative colitis and Crohn's disease.

Chronic nonspecific multiple ulcer of the small intestine segregates in offspring from consanguinity

BACKGROUND AND AIMS

Chronic nonspecific multiple ulcer of the small intestine is a recently proposed enteropathy characterized by persistent blood and protein loss from the small-bowel. We examined possible segregation of the disease in family pedigrees.

METHODS

All cases of the disease diagnosed at our institution were reviewed with respect to particular focuses on the presence of close consanguinity in the families, the enteroscopic findings and the long-term clinical course. The diagnosis was based on persistent occult gastrointestinal bleeding and hypoproteinemia for more than 5 years, and irregularly shaped shallow ulcers in the ileum.

RESULTS

During a 45-year-period, 13 patients were diagnosed as having the disease. There were 11 females and 2 males, with ages ranging from 8 to 37 years at the time of the initial presentation and with those from 13 to 38 years at the diagnosis. Enteroscopy performed in 11 patients with a time duration ranging from 0.5 to 44 years after the diagnosis revealed active ileal ulcers in 10 patients. Parents' consanguineous marriage was verified in 6 patients, two of whom also had siblings with the enteropathy. Another patient without consanguinity had a sibling with protein-losing enteropathy.

CONCLUSION

Chronic nonspecific multiple ulcer of the small intestine seems to segregate in offspring from consanguineous marriage.

Familial aggregation in inflammatory bowel disease: Is it genes or environment?

Inflammatory bowel disease (IBD) develops in genetically susceptible individuals due to the influence of environmental factors, leading to an abnormal recognition of microbiota antigens by the innate immune system which triggers an exaggerated immune response and subsequent bowel tissue damage. IBD has been more frequently found in families, an observation that could be due to either genetic, environmental or both types of factors present in these families. In addition to expanding our knowledge on IBD pathogenesis, defining the specific contribution to familial IBD of each one of these factors might have also clinical usefulness. We review the available evidence on familial IBD pathogenesis.

Perinatal and early life risk factors for inflammatory bowel disease

AIM: To investigate associations between perinatal risk factors and subsequent inflammatory bowel disease (IBD) in children and young adults.

METHODS: Record linked abstracts of birth registrations, maternity, day case and inpatient admissions in a defined population of southern England. Investigation of 20 perinatal factors relating to the maternity or the birth: maternal age, Crohn’s disease (CD) or ulcerative colitis (UC) in the mother, maternal social class, marital status, smoking in pregnancy, ABO blood group and rhesus status, pre-eclampsia, parity, the infant’s presentation at birth, caesarean delivery, forceps delivery, sex, number of babies delivered, gestational age, birthweight, head circumference, breastfeeding and Apgar scores at one and five minutes.

RESULTS: Maternity records were present for 180 children who subsequently developed IBD. Univariate analysis showed increased risks of CD among children of mothers with CD (P = 0.011, based on two cases of CD in both mother and child) and children of mothers who smoked during pregnancy. Multivariate analysis confirmed increased risks of CD among children of mothers who smoked (odds ratio = 2.04, 95% CI = 1.06-3.92) and for older mothers aged 35+ years (4.81, 2.32-9.98). Multivariate analysis showed that there were no significant associations between CD and 17 other perinatal risk factors investigated. It also showed that, for UC, there were no significant associations with the perinatal factors studied.

CONCLUSION: This study shows an association between CD in mother and child; and elevated risks of CD in children of older mothers and of mothers who smoked.

Familial aggregation and antimicrobial response dose-dependently affect the risk for Crohn's disease

BACKGROUND

An increased risk of Crohn's disease (CD) has been reported consistently in first-degree relatives of patients. Our aim was to test whether a combination of CD-associated genes involved in innate immunity and/or antibody responses to microbial antigens may be valuable in identifying healthy relatives at risk.

METHODS

We investigated 86 families from Belgium and northern France, 45 with at least 3 first-degree relatives with CD, 24 with a single case, and 17 control families without inflammatory bowel disease (IBD). The cohort consisted of 186 CD patients, 290 healthy relatives, and 142 controls (total 618). Genetic (NOD2, NOD1, TLR4, CARD8) and serologic markers (ASCA, ACMA, ALCA, ACCA, ASigmaMA, OmpC, CBir1, I2) were determined in all subjects. All Belgian families were prospectively followed up for 54 months.

RESULTS

In multiple-affected families, an increment of affected first-degree relatives and of positive antibodies were additive risks factors for CD (P < 0.0001), independent of NOD2 mutations. When comparing subjects from multiple-affected families, having 3 additional first-degree relatives with CD and 1 additional positive antibody increased the odds for CD to 9.19 (95% confidence interval [CI]: 4.07-20.80). After a follow-up of 54 months among all Belgian families, a total of 4 new diagnoses of IBD were confirmed in the multiple-affected families only, resulting in a 57-fold increase in incidence within multiple-affected families compared to the known incidence of IBD in our region.

CONCLUSIONS

We found an additive risk increment for CD in subjects from multicase families per additional affected relative and per additional positive antibody, independent of NOD2. Furthermore, a very high disease incidence was observed in these multiple-affected families.

Familial aggregation in Crohn's disease and ulcerative colitis in a Norwegian population-based cohort followed for ten years

BACKGROUND AND AIMS

To explore the change in risk among 1st degree relatives of ulcerative colitis (UC) and Crohn's disease (CD) for development of concordant disease in an incidence cohort followed for ten years. Furthermore, we wanted to compare familial and sporadic cases regarding clinical characteristics and the course of the disease.

METHODS

This population-based study included 421 patients with UC and 197 with CD enrolled from 1990 to 1994. Clinical characteristics and the number of 1st degree relatives of the patients were recorded continuously during ten years.

RESULTS

Age at diagnosis in CD patients (OR=0.95, 95% CI: 0.93-0.98) and cumulative relapse rate in UC patients (OR=4.91, 95% CI=1.16, 20.75) were significantly associated to familial clustering. Based on the calculated population prevalence of CD (262/100000) and UC (505/100000), the age-adjusted risk for development of concordant disease was 25.9 and 8.6 among siblings and parents of CD, respectively. In UC, the corresponding risks were 8.6 and 1.5. In the course of ten years the increase in risk was observed only among siblings (28%) and parents (97%) of UC, in contrast to no increase in CD. Moreover, the concordance for UC was high in three generations.

CONCLUSIONS

Our study confirmed the importance of genetic influence on the development of CD. Within an observation period of ten years, the increased concordance and relapse rate in familial UC, might point to a larger genetic component in UC than previously suggested.

Long-term natural history of Crohn’s disease

Crohn’s disease is a chronic inflammatory granulomatous process that usually involves different sites in the intestinal tract. Genetic and environmental factors are thought to play a role in its etiology and pathogenesis. The disorder has a heterogeneous clinical expression and data from tertiary care settings have documented its female predominance, occasional familial nature, and high rate of stricture formation and penetrating disease. It may appear from early childhood to late adulthood, although over 80% are currently diagnosed before age 40 years, usually with terminal ileal and colonic involvement. Several studies have now shown differences in phenotypic clinical expression depending on the initial age at diagnosis, with pediatric-onset disease being more severe and more extensive with more involvement of the upper gastrointestinal tract compared to adult-onset disease. In addition, long-term studies from these tertiary care settings have documented that the disorder may evolve with time into a more complex disease with stricture formation and penetrating disease complications (i.e. fistula and abscess). Although prolonged remission with no evidence of inflammatory disease may occur, discrete periods of symptomatic and active granulomatous inflammatory disease may re-appear over many decades. Long-term studies on the natural history have also suggested that discrete events (or agents) may precipitate this granulomatous inflammatory process.

Granuloma-positive Crohn's disease

BACKGROUND

The epithelioid granuloma is a characteristic histological feature of Crohn's disease. In some pathological classification schemes, the criteria for a definite, probable or possible diagnosis have been listed, with the epithelioid granuloma indicating definite Crohn's disease.

METHODS

In the present evaluation, 247 prospectively evaluated Crohn's disease patients (24.3%), from a consecutively accumulated population database of 1015 patients, were found to have an epithelioid granuloma. The recently devised Montreal classification for Crohn's disease was then applied to this granuloma-positive cohort of Crohn's disease patients to define age at diagnosis for men and women, disease site and disease behaviour.

RESULTS

The investigation showed that patients with Crohn's disease and granulomas were most often diagnosed early in the course of their disease, particularly women. Their disease was often extensive, with ileocolonic and upper gastrointestinal tract involvement. Finally, disease behaviour was most often complex, especially with penetrating disease complications.

CONCLUSION

Using homogeneous (ie, 'reagent-grade') patient cohorts defined by a recently devised classification method for Crohn's disease, the study demonstrated that an epithelioid granuloma may represent a histopathological marker for an early biological event in the etiopathogenesis of Crohn's disease, and this may have predictive significance with respect to the location and clinical behaviour of Crohn's disease.

Application of the Montreal classification for Crohn's disease to a single clinician database of 1015 patients

Crohn's disease involves different gastrointestinal sites and may be characterized by high rates of strictures and penetrating complications. The present study applied the newly described Montreal schema of classification to a large, prospectively accumulated clinical database. In addition, age dependence was evaluated at diagnosis, with regard to disease location and disease behaviour. There were 1015 consecutively evaluated patients (449 male and 566 female). Disease was most often localized in the ileocolon and was usually complex with stricture formation or penetrating complications. For both sexes, with increasing age at diagnosis, Crohn's disease was less extensive, more often localized in the colon alone and characterized by less complex disease behaviour, especially with less penetrating disease complications. Using the Montreal classification for Crohn's disease, these results define the clinical features in a large, single clinician database and demonstrate age dependence in the phenotypic clinical expression of Crohn's disease.

Are there any differences in phenotype or disease course between familial and sporadic cases of inflammatory bowel disease? Results of a population-based follow-up study

BACKGROUND

The influence of familial IBD on phenotype and course of disease in patients with CD and UC has not been studied in population-based cohorts.

AIM

To compare phenotype and course of disease between IBD patients with a first-degree relative with IBD and sporadic cases in a population-based cohort followed prospectively for 5 yr.

METHODS

Family history of IBD was registered at diagnosis and after 1 and 5 yr. Phenotype and course of disease were compared between sporadic and familial cases.

RESULTS

Data for 200 patients with CD and 454 with UC were sufficient for analysis. A first-degree relative with IBD was registered in 14.5% of CD patients and 10.1% of UC patients. The concordance for type of disease was 82% and 70% for CD and UC, respectively. No differences between familial and sporadic cases as regards localization and behavior of disease in CD patients or disease extent in UC patients were observed. In CD patients with colonic involvement, those in the familial group were significantly younger at diagnosis than the sporadic cases. No difference in disease severity in CD patients was observed between the familial and sporadic groups. In UC patients relapse was more frequent in familial cases, but no difference was observed in the need for surgery or medical treatment.

CONCLUSIONS

A family history of IBD does not seem to influence phenotype or to be an important prognostic factor for disease course in IBD patients.

Family and twin studies in inflammatory bowel disease

Studies examining the inheritance of inflammatory bowel disease (IBD) within different family groups have been the basis for recent molecular advances in the genetics of IBD. The derived heritability in Crohn’s disease (CD) is higher than in many other complex diseases. The risk of IBD is highest in first-degree relatives of a CD proband, but first-degree relatives of a proband suffering from ulcerative colitis (UC) and more distant relatives are also at increased risk. Disease concordance rates in IBD have been examined in multiplex families and in three large European twin studies.

New genes in inflammatory bowel disease: lessons for complex diseases?

The chronic inflammatory bowel diseases Crohn's disease and ulcerative colitis are common causes of gastrointestinal disease in northern Europe, affecting as many as one in 250 people. Although mortality is low, morbidity associated with these diseases is substantial. We review the recent advances in the genetics of inflammatory bowel disease, with particular emphasis on the data that have been generated since the discovery of the CARD15 (NOD2) gene in 2001.

Age-dependent phenotypic clinical expression of Crohn's disease

Crohn's disease is a heterogeneous disorder that involves different sites along the length of the gastrointestinal tract. It is usually characterized by a high rate of strictures and penetrating complications. The present study used the modified Vienna classification schema to explore the specific role of age at diagnosis on both disease location and disease behavior. There were 1,015 consecutively evaluated patients, including 449 males and 566 females. Disease was most often localized in the ileocolon and could be most often classified as complex disease (ie, in >70%) with strictures or penetrating complications. For both males and females, with increasing age at diagnosis, disease became less extensive, more often localized in the colon alone, and disease behavior could be characterized as more complex, especially with penetrating disease complications. These results demonstrate the phenomenon of age dependence in the phenotypic clinical expression of Crohn's disease.

Comparison of longstanding pediatric-onset and adult-onset Crohn's disease

INTRODUCTION

Limited information is available on the characteristics of longstanding Crohn's disease with onset in childhood or adolescence.

MATERIALS AND METHODS

In this retrospective study, 224 patients with pediatric-onset Crohn's disease were compared to a group of patients with disease diagnosed as adults.

RESULTS

More than 50% of the patients in the pediatric-onset group were followed for more than a decade, with a mean follow-up of 12.2 years. There were 96 male (42.9%) and 128 female (57.1%) patients. Most had disease diagnosed in adolescence. The female predominance, similar to adult-onset disease, was noted only among patients with disease diagnosed in adolescence (13-19 years), not in childhood. Disease most often involved both ileum and colon (128 of 224; 57.1%). Isolated ileal or colonic disease was less common. Upper gastrointestinal tract disease was present in 42 of 224 (18.8%) patients. The incidence of strictures (28.6%) and penetrating complications (46.4%) was similar to that of adults followed for the same period of time.

CONCLUSION

In pediatric-onset Crohn's disease, female-predominance emerges during adolescence. Pediatric-onset disease is more extensive than adult-onset disease. When followed for an extended period of time, it has high rates of disease complexity, with strictures and penetrating complications similar to adult-onset disease.

IBD: a family affair

The recent molecular advances in the understanding of the genetics of inflammatory bowel disease (IBD) have their grounding in studies examining IBD within different family groups and populations. The risk of IBD is highest in first-degree relatives of an IBD proband but more distant relatives are also at increased risk. The risk is higher for relatives of a CD proband. The risks of developing IBD for 'high-risk' relatives might be as great as 1 in 3 but in general first-degree relatives have a 1 in 10-20 risk. Three recent systematic studies have identified a total of 326 European twin pairs to examine disease concordance rates. The derived heritability in Crohn's disease is greater than for many complex diseases and is currently under detailed examination. Strong concordance has been shown, in particular for disease type and disease location, in multiplex families and twin studies. More than 75% children are diagnosed with IBD at a younger age than their parents but true genetic anticipation appears unlikely.

Natural history and clinical behavior of Crohn's disease extending beyond two decades

Crohn's disease is a heterogeneous inflammatory disorder characterized by strictures or perforating complications. Information on natural history is limited. In the present study, 150 patients with long-standing Crohn's disease, including 81 females and 69 males, were seen continuously by a single clinician for at least 20 years. Additional retrospective data were available extending for >40 years and 13 have now died, usually with an advanced malignancy. To evaluate disease expression, phenotypic clinical characteristics defined by the 1998 Vienna classification for Crohn's disease were used and included age at diagnosis, location of disease, and disease behavior at the time of diagnosis or 10 years or 20 years after diagnosis. Most patients were initially diagnosed before the age of 40 years (94%) and had ileocolonic disease (65.3%). At diagnosis, both females and males were most often classified with inflammatory disease (nonstenosing, nonpenetrating); however, over the course of the disease, particularly in the first decade, decreased numbers of patients with inflammatory disease and increased numbers with penetrating disease were seen. In addition, some with stenosing disease eventually developed penetrating disease. Disease localized to ileum alone was most often complicated by stricture formation, whereas ileocolonic disease was usually complicated by a penetrating complication. This shift in disease behavior indicates that Crohn's disease is a dynamic process that phenotypically evolves and progresses with time.