CLINICAL CHARACTERISTICS OF CROHNS-DISEASE IN 72 FAMILIES

Background & Aims: Familial aggregation argues for genetic susceptibil ity to Crohn's disease, The aim of this study was to compare the age o f onset and the clinical features of Crohn's disease between patients with familial disease and those with sporadic disease and investigate the concordance for disease location and type among relatives with Cro hn's disease, Methods: Seventy-two families with 2 (n = 55), 3 (n = 8) , 4 (n = 6), and 5 or more (n = 3) affected first-degree relatives wer e selected for the study, A population of 1377 patients with sporadic nonfamilial Crohn's disease was used for comparison, Results: Clinical data were obtained from 176 patients with familial Crohn's disease (7 9 men and 97 women), Median age at onset was younger in familial Crohn 's disease than in sporadic cases: 22 vs, 26.5 years (P < 0.01). In fa milial cases, fewer patients had exclusively colonic involvement and m ore patients had both small bowel and colonic involvement, Among relat ives of families with 2 affected members, 56% were concordant for dise ase location and 49% for disease type, These percentages reached 83% a nd 76%, respectively, within families with more than 2 affected member s. Conclusions: Patients with familial Crohn's disease are characteriz ed by an early age at onset with more extensive disease and may repres ent a homogeneous clinical subgroup with a particularly strong genetic influence.