Screening for Celiac Disease in Asymptomatic First-Degree Relatives
Order tissue transglutaminase IgA (tTG-IgA) test with documentation of normal total serum IgA levels now, as this 18-month-old child is a first-degree relative of a celiac disease patient and should be screened regardless of symptoms. 1
Rationale for Screening
First-degree relatives of celiac disease patients have significantly elevated risk (approximately 10-15% prevalence compared to 0.5-1% in the general population) and should be offered screening even when asymptomatic. 1, 2
The American Gastroenterological Association explicitly recommends that all first-degree relatives of confirmed celiac disease patients should be offered screening, independent of symptom status. 1
While the child currently has normal growth and weight, celiac disease can be entirely asymptomatic yet still cause long-term complications including poor growth, osteoporosis, and increased risk of lymphoma if left undiagnosed. 3, 4
Appropriate Screening Test
Measure IgA tissue transglutaminase (tTG-IgA) antibodies with documentation of normal total serum IgA levels as the primary screening test. 1, 5
If IgA deficiency is detected (occurs in 1-3% of celiac patients), use IgG tTG and deamidated gliadin peptide antibodies instead. 1, 5
The child must be consuming gluten-containing foods at the time of testing, as a gluten-free diet causes false-negative results. 5, 6
Follow-Up Screening Protocol
If the initial screening is negative, repeat screening within 2 years, then again after 5 years from initial testing. 7, 1
More frequent screening is warranted if the child develops symptoms suggestive of celiac disease (diarrhea, poor growth, abdominal pain) or develops other autoimmune conditions like type 1 diabetes. 7, 1
Consider HLA-DQ2/DQ8 testing at initial screening to stratify future risk—absence of both HLA-DQ2 and HLA-DQ8 effectively rules out celiac disease and eliminates the need for future screening. 1, 6
Why Not the Other Options
Reassurance alone (Option A) is inappropriate because:
- The child has a documented 10-15% risk of developing celiac disease based on family history alone. 2
- Current guidelines explicitly recommend screening all first-degree relatives regardless of symptoms. 1
- Asymptomatic celiac disease can still cause significant long-term morbidity if undetected. 3, 4
Starting a gluten-free diet (Option C) is premature and potentially harmful because:
- No diagnosis has been established—the child may not have celiac disease. 1
- A gluten-free diet initiated before testing will cause false-negative serologic and biopsy results, making future diagnosis impossible without gluten rechallenge. 5, 6
- Unnecessary dietary restrictions place significant psychosocial and nutritional burden on the child and family. 7, 8
- Gluten-free diets should only be initiated after biopsy-confirmed celiac disease. 7, 1
Important Caveats
Monitor growth parameters closely during follow-up, as poor growth velocity may indicate undiagnosed celiac disease even with negative initial serology. 1
If serologic testing is positive, duodenal biopsy remains essential for diagnosis confirmation before committing the child to lifelong dietary restrictions. 1, 5
The child should remain on a gluten-containing diet throughout the diagnostic process until biopsy confirmation (if needed). 5, 6