The aim of this study is to report our 3years experience with the screening of congenital disorders of glycosylation. A common isoelectric focusing method with immunofixation was used for analysis of serum transferrin and α1-antitrypsin, apart from several other procedures. A group of about 1000 individuals, both healthy controls and patients, mostly with signs of a metabolic disease were examined. Here we present an overview of 1) hypoglycosylation findings, 2) distribution of protein variants, 3) misguiding rare Tf variants found in our set, and 4) association of some phenotypes with various diseases.
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.
Human transferrin (Tf) shows genetic polymorphisms, which may interfere in the screening of congenital disorders of glycosylation (CDG). Isoelectric focusing followed by direct immunofixation was used for Tf analysis in controls and several groups of patients. Equivocal results in one case have been recognized as a rare Tf CD variant. A higher incidence of some genetic variants has been reported in connection with certain diseases; of the seven Tf phenotypes detected in our set of samples, an apparently higher frequency of Tf C1C2 variant found in some groups of patients was not significant.
Mycobacterioses are less frequently occurring but serious diseases. In recent years, at a global level, the incidence of mycobacterioses induced by the rapidly growing species Mycobacterium abscessus (M. a.), which is considered to be the most resistant to antibiotics and most difficult to treat, has been on the rise. Correct identification to the level of the subspecies (M. a. abscessus, M. a. massiliense, and M. a. bolletii) and determination of its sensitivity to macrolides, which are the basis of combination therapy, are of principal importance for the management of the disease. We describe five cases of mycobacterioses caused by M. a., where the sequencing of select genes was performed to identify the individual subspecies and antibiotic resistance. The analysis of the rpoB gene showed two isolates each of M. a. abscessus and M. a. massiliense and one isolate of M. a. bolletii. The complete (full length) erm(41) gene responsible for the development of inducible resistance to macrolides was demonstrated in both M. a. abscessus and M. a. bolletii isolates. A partially deleted and non-functional erm(41) gene was demonstrated in M. a. massiliense isolates. The subsequent sequencing of the full length erm(41) gene products showed, however, the mutation (T28→C) in both isolates of M. a. abscessus, causing a loss of the function and preserved sensitivity to macrolides. The antibiotic sensitivity testing confirmed that both the isolates of M. a. abscessus and M. a. massiliense were sensitive to clarithromycin even after prolonged 14-day incubation. The inducible resistance to clarithromycin was maintained only in M. a. bolletii. Thus, the sequence analysis of the erm(41) gene can reliably identify the preservation of sensitivity to macrolides and serve as an important tool in the establishment of therapeutic regimens in cases of infections with M. abscessus.
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