Anticipation in familial Crohn's disease

Background—Offspring with a family historyof Crohn's disease have an earlier age of onset than their parents.This might be due to genetic anticipation, characterised by earlierand/or more severe disease in subsequent generations.
Aims—To investigate the possibility of geneticanticipation in affected parent-child pairs with Crohn's disease fromFrance and Belgium.
Patients and methods—In a cohort of 160 multiplyaffected families with Crohn's disease, 57 parent-first affected childpairs were detected. Clinical characteristics (age at diagnosis,disease extent, and type) of both parents and children were registered and compared.
Results—Children were younger than their parentsat diagnosis in 48/57 (84%) pairs. The median age at diagnosis was 16 years younger in children than in parents (p<0.0001). However, thedifference was related to the age at diagnosis in the parents and wasnot present in 12 parent-child pairs with an early age at diagnosis forthe parents. In most cases, disease extent and type were not consideredmore severe in children than in parents. Parental sex affected neitherage at diagnosis nor extent and type of disease in children.
Conclusion—Patients in the second affectedgeneration acquire their disease at an earlier time in life in some butnot all familial cases of Crohn's disease. Several explanationsincluding genetic anticipation and environmental factors might explainthis phenomenon.

Keywords:Crohn's disease; familial; geneticanticipation