5 Phenotypic characteristics of p.E92K mutation in adults with cystic fibrosis (CF) in Russia

Abstract

The main reason for development of CF for the Chuvash − the fifth in population number (1.5 mln) nationality in Russia is of the “mild” p.E92K mutation (p.Glu92Lys, c.274G>A). Objective: To identify the clinical and functional characteristics of the course of CF in the patients-carriers of p.E92K mutation. Materials and Methods: Group 1: 26 adult CF patients homozygous or heterozygous for E92K, group 2: 103 adult patients homozygous for F508del. Age, age diagnosis, BMI, level of chloride in sweat, spirometry parameters, frequency of some complications [CF related diabetes (CFRD), liver cirrhosis with portal hypertension (LCPH), distal intestinal obstruction syndrome (DIOS)/meconium ileus (MI) in past medical history, cholelithiasis, urolithiasis, pulmonary hypertension (PH), asthma] were estimated. Results are described as mean±SD/median (IQR). Results: The median age group 1 was: 26.0 (5.95) years, higher than in the group 2 − 23.6 (6.5) years (p = 0.007); age diagnosis of patients with E92K was: 13.3 (9.2), higher than among homozygous for F508del − 1.9 (4.5) years (p< 0.001). There was no significant difference in the level of chloride in sweat (101±30.5mmol/l vs 103±32mmol/l respectively) in the two groups. The spirometry parameters, BMI, the frequency of LCPH, DIOS/MI, cholelithiasis, urolithiasis, asthma and PH had not significant difference. CFRD had frequency in the group of the patients homozygous for F508del, and CFRD in group p.E92K was never once identified (p = 0.046). Conclusion: p.E92K mutation in patients-carriers is associated with late onset age, significant low frequency of CERD, what is likely connected with the “mildness” of this mutation.