Silent celiac disease is frequent in the siblings of newly diagnosed celiac patients.

Background/aims: Celiac disease is caused by environmental and genetic factors, and the relatives of celiac patients are at higher risk of developing celiac disease than the general population. This prospective study evaluates the prevalence of celiac disease in the asymptomatic siblings of celiac patients.

Methods: Forty-eight siblings (22 males; mean age 13 years) of 39 celiac children (20 males; mean age 4 years), and 120 siblings (55 males; mean age 33 years) of 55 adult celiac patients (12 males; mean age 31 years) were serologically screened for celiac disease. Positive cases were considered for endoscopic duodenal biopsies.

Results: Forty of the 168 asymptomatic siblings (23.8%) were affected by celiac disease. There were no differences between the index cases with and without affected siblings in terms of age at diagnosis, symptoms at onset, order of birth, associated disorders or other affected relatives. The male siblings of pediatric patients were affected in 40.9% of cases and female siblings in 26.9%; the corresponding figures for adults were 16.4 and 23.1%.

Conclusions: Silent celiac disease is 24-48 times more frequent in the siblings of celiac patients than in the general population. No predictive factors for sibling involvement were found. Adult females seem to tolerate gluten less than adult males.