Genetic variants of transferrin in cystic fibrosis

Background: Genetic polymorphism of serum transferrin (Tf) was studied in order to differentiate between protein genetic variants and congenital disorders of glycosylation (CDG), further focusing on unusual findings. Methods: Screening of Tf hypoglycosylation was carried out by isoelectric focusing with direct immunofixation and Coomassie blue staining in 100 healthy controls and a group of 1247 patients with various symptoms and diagnoses. Results: Of the seven different genotypes detected, a significantly higher (p=0.004) frequency of Tf C1C2 was found among 92 patients with cystic fibrosis; only the most severe DF508 mutation (in either homozygous or heterozygous form) was regularly present in the carriers of this Tf genotype, in contrast to those with the Tf C1C1 variant. Conclusions: Association of Tf C2 allele with various malfunctions has been noticed before, but is so far unresolved. This is the a report on increased frequency of Tf C1C2 genotype found in cystic fibrosis. Analysis of larger samples and independent confirmation of our results are needed.