['Mucins are excellent candidates for contributing to the presence of meconium ileus (MI) in cystic fibrosis (CF) due to their extensive genetic variation and known function in intestinal physiology. The length of variants in mucin central repetitive regions has not been explored as "risk" factors for MI in CF.', 'We investigated the length polymorphisms in the central repetitive regions of MUC1, MUC2, and MUC5AC by Southern blot and tested for association with MI in CF subjects.', 'No significant associations were found for the allele sizes of any of the genes with respect to the prevalence of MI (p values=0.33, 0.16, and 0.71 for MUC1, MUC2, and MUC5AC, respectively).'] Is meconium ileus in cystic fibrosis linked to central repetitive region length variation in MUC1 , MUC2 , and MUC5AC?