Genetics of Mucopolysaccharidosis Type IV (Morquio Disorder) in Patients from Azerbaijan

Abstract

Genetic screening in the Azerbaijan Republic for mucopolysaccharidosis disorder has been implemented. The purpose of the work was to study types of mucopolysaccharidosis mutations and discuss ways of disorder prophylaxis in the family with parents of reproductive ages. Materials and methods. Material for studies was collected in the specialized children medical centers in Baku city, Azerbaijan, as well as in the field works in the regions of the Republic for 2018–2022. Patients were chosen during clinical examinations by pediatrician and geneticist. To screen mucopolysaccharidosis disorder a complex of modern molecular-genetic diagnostics methods have been applied. 56 patients were identified in the age varied between six months and 28 years. Gender differentiation was as follows: 15 males and 11 females. Blood sampling was done onto dry blood sample cards. All patients have undergone enzyme analysis for all mucopolysaccharidosis types. Results and discussion. The carried-out screening of enzymatic analysis allowed us to identify 26 patients with the N-aсetylgalaсtosamine-6-sulfat sulfatase enzyme deficit out of disorder suspicious 56 persons. And that was specific for mucopolysaccharidosis type IV A. That counted 46.4% of all studied patients. Seven mutation types in homozygous, double heterozygous (compound) and heterozygous state were identified. All mutations have nucleotide substitution. Practical application of the results is being discussed. Mucopolysaccharidosis type IV frequency was higher than other mucopolysaccharidosis disorder types. In eight patients the level of the enzyme was very low and varied between <0.1 (LOD) μmol/L/h and <0.3 (LOD) μmol/L/h, which is specific for homozygous or double heterozygous state, when norm is ≥2.0 mol/L/h. In 18 patients the activity level of N-aсetylgalaсtosamine-6-sulfate sulfatase enzyme was almost half reduced (<0.6 (LOD) μmol/L/h - <0.1 (LOD)), which speaks to heterozygous state of disorder. Conclusion. Thus, for the first time populational study of mucopolysaccharidosis disorder by means of molecular-genetic modern complex has been carried out. Molecular-genetic analysis allowed our identification of 7 GALNS gene mutation types: 553 C>T, 439 T>A, 1283 A>G, 157 G>A, 463 G-T, 1018 G-T and 443 A>G. These mutations have nucleotide substitutions and have been priory described in references