The ICM method in clinical practice

Abstract

Introduction. Not always patients with cystic fibrosis (CF) have clinical manifestations characteristic of the disease, which is determined by the patient’s genotype. The «ICM» method plays a special role in diagnostics with borderline sweat test values and rare genetic variants.

Objective: to evaluate the use of the intestinal current measurement (ICM) method for clinical practice.

Methods. ICM was carried out according to the European SOP V2.7_26.10.11. 154 people were examined: 18 healthy people (control group), 36 patients with suspected cystic fibrosis, 100 patients with cystic fibrosis (genetic variants of various classes – I, II, IV, V) of which 21 patients with rare genetic variants not described earlier, the effectiveness of targeted therapy was assessed in 34 patients.

Results. 36 patients with suspected CF (carriers of 1 CFTR variant, atypical clinical picture) were examined. The diagnosis was removed in 23 patients, and confirmed in 10. The following genetic variants were identified and described for the first time: 1898+2T>C, G1047S, 3321delG, 712-1G>T, Q1352P, c.1584+18672A>G, E873X, D443fs, W277X, W361X, D579Y, N505H, E403D, S1455X. The function of ion channels was studied in the variants typical for the Russian Federation: E92K, W1282R, N1303K, R334W, 3272-16T>A, in carriers of complex alleles F508del;L467F, S466X;R1070Q and E217G;G509D. The effectiveness of targeted therapy was assessed in 34 patients.

Conclusions. The ICM method helps clinical physicians establish or exclude the diagnosis of cystic fibrosis, especially in the case of newly identified genetic variants of the CFTR gene, and assess the effectiveness of therapy with CFTR modulators.