Celiac disease is a chronic, immune-mediated, systemic disorder caused by intolerance to gluten — a protein present in rye, barley, and wheat grains — that affects genetically predisposed individuals.
Due to its wide spectrum of clinical manifestations, celiac disease resembles a multisystemic disorder. Its most common gastrointestinal (GI) symptoms include chronic diarrhea, weight loss, and abdominal distention. However, celiac disease can also manifest in myriad extraintestinal symptoms, ranging from headache and fatigue to delayed puberty and psychiatric disorders, with differing presentations in children and adults.
To date, the only treatment is adopting a gluten-free diet (GFD). Although key to preventing persistent villous atrophy, the main cause of complications in celiac disease, lifelong adherence to GFD is challenging and may not resolve all clinical issues. These shortcomings have driven recent efforts to develop novel therapeutic options for patients with this disease.
Here are five things to know about celiac disease.
1. Rising Prevalence of Celiac Disease and Other Autoimmune Disorders Suggests Environmental Factors May Be at Play.
Gluten was first identified as the cause of celiac disease in the 1950s. At that time, the condition was thought to be a relatively rare GI disease of childhood that primarily affected people of European descent, but it is now known to be a common disease affecting those of various ages, races, and ethnicities.
A 2018 meta-analysis found the pooled global prevalence of celiac disease was 1.4%. Incidence has increased by as much as 7.5% annually over the past several decades.
Increased awareness among clinicians and improved detection likely play a role in the trend. However, the growth in celiac disease is consistent with that seen for other autoimmune disorders, according to a 2024 update of evidence surrounding celiac disease. Shared environmental factors have been proposed as triggers for celiac disease and other autoimmune diseases and appear to be influencing their rise, the authors noted. These factors include migration and population growth, changing dietary patterns and food processing practices, and altered wheat consumption.
2. No-Biopsy Diagnosis Is Accepted for Children and Shows Promise for Adults.
It is estimated that almost 60 million people worldwide have celiac disease, but most remain undiagnosed or misdiagnosed, or they experience significant diagnostic delays.
Prospective data indicate that children with first-degree relatives with celiac disease are at a significantly higher risk of developing the condition, which should prompt screening efforts in this population.
The 2023 updated guidelines from the American College of Gastroenterology (ACG) state that serology testing plays a central role in screening. This commonly involves serological testing for positive serological markers of the disease, including immunoglobulin A (IgA), anti-tissue transglutaminase IgA (tTG-IgA), anti-deamidated gliadin peptide, or endomysial antibodies.
To confirm diagnosis, clinicians have relied on intestinal biopsy since the late 1950s. The ACG still recommends esophagogastroduodenoscopy with multiple duodenal biopsies for confirmation of diagnosis in both children and adults with suspicion of celiac disease. However, recent years have seen a shift toward a no-biopsy approach.
For more than a decade in Europe, a no-biopsy approach has been established practice in pediatric patients, for whom the burden of obtaining a histological confirmation is understandably greater. Most guidelines now permit children to be diagnosed with celiac disease in the absence of a biopsy under specific circumstances (eg, characteristic symptoms of celiac disease and tTG-IgA levels > 10 times the upper limit of normal). The ACG guidelines state that "this approach is a reasonable alternative to the standard approach to a [celiac disease] diagnosis in selected children."
The ACG does not recommend a no-biopsy approach in adults, noting that, in comparison with children, there is a relative lack of data indicating that serology is predictive in this population. However, it does recognize that physicians may encounter patients for whom a biopsy diagnosis may not be safe or practical. In such cases, an "after-the-fact" diagnosis of likely celiac disease can be given to symptomatic adult patients with a ≥ 10-fold elevation of tTG-IgA and a positive endomysial antibody in a second blood sample.
A 2024 meta-analysis of 18 studies involving over 12,103 adult patients from 15 countries concluded that a no-biopsy approach using tTG-IgA antibody levels ≥ 10 times the upper limit of normal was highly specific and predictive of celiac disease.
3. Celiac Disease Is Associated With Several Life-Threatening Conditions.
Emerging data indicate that gastroenterologists should be vigilant in screening patients with celiac disease for several other GI conditions.
Inflammatory bowel disease and celiac disease have a strong bidirectional association, suggesting a possible genetic link between the conditions and indicating that physicians should consider the alternate diagnosis when symptoms persist after treatment.
Given the hypervigilance around food and diet inherent to celiac disease, patients are at an increased risk of developing avoidant/restrictive food intake disorder, according to a 2022 retrospective study.
In 2023, Italian investigators showed that children with celiac disease have an elevated prevalence of functional GI disorders even after adopting a GFD for a year, regardless of whether they consumed processed or natural foods. It was unclear whether this was due to a chronic inflammatory process or to nutritional factors.
Complications resulting from celiac disease are not limited to GI disorders. For a variety of underlying pathophysiological reasons, including intestinal permeability, hyposplenism, and malabsorption of nutrients, patients with celiac disease may be at a higher risk for non-GI conditions, such as osteopenia, women's health disorders (eg, ovarian failure, endometriosis, or pregnancy loss), juvenile idiopathic arthritis in children and rheumatoid arthritis in adults, certain forms of cancer, infectious diseases, and cardiomyopathy.
4. GFD Is the Only Treatment, but It's Imperfect and Frustrating for Patients.
GFD is the only treatment for celiac disease and must be adhered to without deviation throughout a patient's life.
Maintaining unwavering adherence reaps considerable benefits: Improved clinical symptoms, robust mucosal healing, and normalization of serological markers. Yet it also takes a considerable toll on patients. Patients with celiac disease struggle with a host of negative physical, psychological, and social impacts. They also report a higher treatment burden than those with gastroesophageal reflux disease or hypertension, and comparable with end-stage renal disease.
GFD also poses financial challenges. Although the price of gluten-free products has decreased in recent years, they still cost significantly more than items with gluten.
Adherence to GFD does not always equate to complete mucosal recovery. While mucosal recovery is achieved in 95% of children within 2 years of the diet's adoption, only 34% and 66% of adults obtain it within 2 and 5 years, respectively.
GFD may lead to nutrient imbalances because gluten-free foods are typically low in alimentary fiber, micronutrients (eg, vitamin D, vitamin B12, or folate), and minerals (eg, iron, zinc, magnesium, or calcium). With higher sugar and fat content, GFD may leave patients susceptible to unwanted weight gain.
The pervasiveness of gluten in the food production system makes the risk for cross-contamination high. Gluten is often found in both naturally gluten-free foods and products labeled as such. Gluten-sensing technologies, some of which can be used via smartphone apps, have been developed to help patients identify possible cross-contamination. However, the ACG guidelines recommend against the use of these technologies until there is sufficient evidence supporting their ability to improve adherence and clinical outcomes.
5. Novel Therapies for Celiac Disease Are in the Pipeline.
The limitations of GFD as the standard treatment for celiac disease have led to an increased focus on developing novel therapeutic interventions. They can be sorted into five key categories: Modulation of the immunostimulatory effects of toxic gluten peptides, elimination of toxic gluten peptides before they reach the intestine, induction of gluten tolerance, modulation of intestinal permeability, and restoration of gut microbiota balance.
Three therapies designed to block antigen presentation by HLA-DQ2/8, the gene alleles that predispose people to celiac disease, show promise: TPM502, an agent that contains three gluten-specific antigenic peptides with overlapping T-cell epitopes for the HLA-DQ2.5 gene; KAN-101, designed to induce gluten tolerance by targeting receptors on the liver; and DONQ52, a multi-specific antibody that targets HLA-DQ2. The KAN-101 therapy received Fast Track designation by the US Food and Drug Administration in 2022.
These and several other agents in clinical and preclinical development are discussed in detail in a 2024 review article. Although no therapies have reached phase 3 testing, when they do, it will undoubtedly be welcomed by those with celiac disease.
John Watson is a freelance writer in Philadelphia.