Familial prevalence of coeliac disease: a twenty-year follow-up study.

BACKGROUND: The genetic predisposition of coeliac disease (CD) is well known. Previous studies of first-degree relatives of coeliac patients have shown that as many as 10% have the disease. In 1981, we published a study in which all first-degree relatives of 32 index patients with CD were investigated by small-bowel biopsy. We found 2 relatives (2%) with CD. The present study is a re-investigation of all first-degree relatives of the same index patients performed 20-25 years after the first study to reveal any new cases of CD in this high-risk population. METHODS: All 120 first-degree relatives were screened for CD by means of serological markers of CD. The relatives with positive markers were submitted to small-bowel biopsy. RESULTS: Eight new cases of CD were found among the relatives. Two had been investigated by small-bowel biopsy 20 years previously, when they had only minor mucosal changes not classified as CD. The other six new cases of CD were found among offspring of the index patients and were born after completion of the previous study. Thus no new case of CD was found among those relatives who had a completely normal small-bowel biopsy 20-25 years previously. CONCLUSIONS: The high prevalence of CD among first-degree relatives of coeliac patients (8.3% in this study) supports the need to screen for CD in this high-risk population. Even relatives with only mild enteropathy should be followed carefully, since some may subsequently develop CD.