Fine mapping a gene for pediatric gastroesophageal reflux on human chromosome 13q14

Genetics of enteric neuropathies

Abnormal development or disturbed functioning of the enteric nervous system (ENS), the intrinsic innervation of the gastrointestinal tract, is associated with the development of neuropathic gastrointestinal motility disorders. Here, we review the underlying molecular basis of these disorders and hypothesize that many of them have a common defective biological mechanism. Genetic burden and environmental components affecting this common mechanism are ultimately responsible for disease severity and symptom heterogeneity. We believe that they act together as the fulcrum in a seesaw balanced with harmful and protective factors, and are responsible for a continuum of symptoms ranging from neuronal hyperplasia to absence of neurons.

Epidemiology of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD), a common disorder in Western society, is less seen in Asian countries, but there is an evidence that the incidence of GERD and its complications is rising. Many factors are believed to be responsible for the pathogenesis of GERD. In addition to some recognized factors, the role of other factors, such as obesity and Helicobacter pylori infection, in the pathogenesis of GERD is still unclear. Furthermore, GERD is believed to be associated with the development of many other diseases. This review summarizes the prevalence and risk factors of GERD and its complications.

A retrospective, case-control pilot study of the natural history of pediatric gastroesophageal reflux

The duration of gastroesophageal reflux disease (GERD) is an important factor in the development of esophageal complications. The objective of this study was to examine in a retrospective, case-controlled manner the prevalence of GERD in adults who were diagnosed with GERD in infancy or early childhood. Infants and children with nonsyndromic GERD diagnosed by an experienced pediatric gastroenterologist from 1976 to 1980 and control subjects seen for well-child care from 1980 to 1985 were included in this study. The subjects were located and contacted by telephone or mail and administered a brief structured questionnaire relating to their current history of GERD. GERD-A was defined as weekly heartburn or regurgitation of any severity, and GERD-B was defined as monthly heartburn or regurgitation greater than mild in severity. Sixty-five participants (31 patients and 34 controls) returned completed questionnaires and were subdivided into the three study groups as follows: Infant (15), Child (16), and Control (34). The prevalence of adulthood GERD-A was 13, 31, and 21% in the Infant, Child, and Control groups, respectively. Similarly, the prevalence of adulthood GERD-B was 20%, 44%, and 24%, respectively. The Child group tended to report more severe heartburn than the other groups. The Infant group tended to report more frequent regurgitation, and the Child group also reported a higher prevalence of nocturnal heartburn and more frequent use of GERD medications, although these were not statistically significant. These data suggest that pediatric GER is a heterogeneous disorder and that GERD occurring after infancy may be more predictive of the presence of GERD during adulthood. Longitudinal follow-up of a larger number of children is needed to answer the question of when classic adulthood GERD begins.

Genetics of pediatric gastroesophageal reflux

PURPOSE OF REVIEW

Recent advances in molecular genetics clearly demonstrate that a patient's susceptibility to developing a common disease is the result of an underlying genetic predisposition. Gastroesophageal reflux disease (GERD) is proving to be no exception. The results of family and twin studies have identified an inherited tendency toward developing the disease, and a locus common to multiple families with severe GERD has been found on 13q14, known as GERD1.

RECENT FINDINGS

While it is clear that there are several genes that control susceptibility to GERD, recent advances are refining the location of GERD1. Genes associated with syndromic GERD may offer clues as to the nature of nonsyndromic GERD genes, and all cases of the disease may not be due to mutations in genes that follow simple Mendelian laws.

SUMMARY

While the pathology of GERD remains elusive, molecular genetic approaches offer the clearest path to elucidating the underlying mechanisms of the disease. Discovering the genes that control susceptibility to GERD will provide improved diagnostics and suggest new pharmacological agents for improved treatment. Future efforts should focus on identification of these genes, and clinicians with access to large GERD patient populations should collaborate with geneticists to accomplish this task. Mapping studies should be undertaken in populations of patients with infantile-onset and adult-onset GERD. Future epidemiologic and twin studies will be of limited value, unless the studies are designed to deliver more than simply confirmatory evidence that there is a hereditable component to GERD.

Decisions in diagnosing and managing chronic gastroesophageal reflux disease in children

Gastroesophageal reflux disease (GERD) presents in different ways in children, most commonly with vomiting, or with esophageal symptoms such as regurgitation, heartburn, or dysphagia. Extraesophageal symptoms and signs also frequently occur. Less well recognized is that abdominal pain is a relatively common mode of presentation. Although abdominal pain is common in school-aged children, GERD and other acid-related disorders such as peptic ulcer disease are relatively uncommon causes of such. A careful history will usually determine whether an acid-related disorder is in the differential diagnosis of abdominal pain. Early detection and treatment of GERD in children may prevent, attenuate, or heal complications such as failure to thrive or feeding refusal as well as pulmonary, ear-nose-and-throat disorders, erosive esophagitis, and peptic stricture. In children with persistent or severe symptoms and/or complications of GERD such as erosive esophagitis, the major treatment options are pharmacologic management with acid-suppressing medication, specifically proton pump inhibitors (PPIs), or antireflux surgery. For many patients, PPI treatment offers advantages over surgery. When given in adequate doses, PPIs can safely effect relief of GERD symptoms and healing of esophagitis in children. Antireflux surgery may work well in selected patients, but it carries significant risk of morbidity, including high failure rates, even in the short term. Some postoperative studies report that more than 60% of patients are back on medical treatment with proton pump inhibitors for recurrence of GERD symptoms, and a similar percentage have new symptoms that were not present before surgery. Death is uncommon but does occur and is an unacceptable risk in an otherwise healthy, low-risk individual. Laparoscopic surgery may have some disadvantages compared with open surgery, including a higher rate of redo operations. Studies show that many children undergo surgery for unclear indications, often with few preoperative diagnostic studies. The availability of highly effective medical therapy, together with more careful selection of patients for surgery, may result in better patient outcomes, with much lower operative rates.