Twenty-four families with two or more members affected with coeliac disease were recruited for this study (fig 1). Nine of these families (Nos 1, 3, 4, 6, 30, 32, 39, 43, and 44) have been used in a previous study of candidate regions.16 All the families were of northern European ancestry. Twelve of the families were recruited from the UK, nine from Sweden, two from Switzerland, and one from The Netherlands. All affected family members had symptomatic disease and were diagnosed according to the revised criteria formulated by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN).20 Families consisted of 88 affected subjects, 36 male and 52 female, giving a male to female ratio of 1:1.5. The age at diagnosis ranged from 9 months to 74 years with a mean of 25 years. Blood samples and clinical data were all collected with informed consent and ethical review board approval. All family members were typed for the HLA-DQ A1*0501 and B1*0201 alleles by PCR-SSP.21 Ninety-nine percent of affected subjects in the families studied had HLA class II genotypes compatible with possession of the DQA1*05, B1*02 alleles.