Specificities of Sanfilippo A syndrome laboratory diagnostics

Abstract

Mucopolysaccharidosis type IIIA (MPS IIIA) occurs due to the deficiency of lysosomal enzyme heparan-N-sulfatase (sulfamidase), which is caused by mutations in the SGSH gene. Aim. To identify the characteristics of biochemical diagnosis of MPS IIIA and determine the prevalence of major mutations R74C and R245H in the SGSH gene in Ukrainian patients. Methods. After all the required phases of laboratory diagnosis of this disease, the diagnosis of MPS IIIA was confirmed in 12 patients from 12 families. The level of sulfamidase activity in leukocytes did not exceed 36 % of the control in all patients. Due to very low sulfamidase activity in leukocytes it is sometimes difficult to interpret the results of the analysis which may lead to false-negative or false-positive diagnosis of MPS IIIA. Results. The analysis of the results of molecular investigation of the patients' samples showed that the incidence of mutation R74C was 17/24 (70.8 %), the incidence of mutation R245H was 2/24 (8.3 %). The total incidence of major mutations R74S and R245H among the patients with MPS IIIA in Ukraine was the highest amongEuropean countries -11 out of 12 patients, these mutations were found in at least one allele. Conclusions. Given very high prevalence of major mutations R74S and R245H in the SGSH gene among the patients with MPS IIIA in Ukraine -79.1 % -it is appropriate to have the screening of mutations in the diagnostic algorithm along with the definition of biochemical sulfamidase activity to prevent false-negative or false-positive diagnosis of Sanfilippo syndrome A.

Bioinformatics classification of mutations in patients with Mucopolysaccharidosis IIIA

“…However, supportive evidence is necessary for validation of these prediction methods. Based on experimental studies (Esposito et al 2000; Héron et al 2011; Knottnerus et al 2017; Muschol et al 2004; Perkins et al 1999; Sidhu et al 2014; Trofimova et al 2014; Weber et al 1997), we selected three mutants R74C, S66W, and R245H for our prediction analysis. As predicted by the multiple sulfatase sequence alignment, R74 is the analogous residue in the SGSH protein.…”

Molecular-genetic characterization of Ukrainian patients with mucopolysaccharidosis IIIA: identification of three new mutations in the heparan-N-sulfatase gene

“…The material of the research was the biological material (blood) of the patients with MPS ІІІ А (23 children from 21 family), whose diagnosis was confirmed by biochemical methods with the determination of the activity of heparan-N-sulfatase in lysosomes, as well as of their 47 relatives (siblings and parents) from different regions of Ukraine [13,14]. The age of patients at the moment of the diagnosis determination was 5 ± 1 years; there were 15 boys and 8 girls.…”

“…DNA was extracted from the whole blood using the commercial kits NeoSorb (Neogen, Ukraine). The identification of major mutations R74C and R245H was conducted by the RFLP-analysis, as described in our publication [13]. For R74C detection: forward primer 5'-TCACAGTCCCAGCCTCCCTACTCC-3', reverse primer 5'-CCCGGGATCCCAGGGATGGG AGAC-3', digestion by BstFNI.…”

“…The missence-mutations R74C and R245H are the major for European populations, as their total frequency varies from 56 % in Germany, Poland, and the Netherlands to 33 % in Italy [10][11][12]. According to the data of our previous studies, in Ukraine the total frequency of these major mutations in SGSH gene is 64.58 % [13], other kinds of mutations in this gene in patients with MPS ІІІ А have not been estimated.…”

Нейропатичні Форми Лізосомних Хвороб Накопичення В Україні

“…На відміну від МПС І і ІІ типів МПС ІІІ типу (хвороба Санфіліппо) є суто нейродегенеративним захворюванням, що об'єднує гетерогенну групу нозологій з автосомно-рецесивним типом успадкування, спричинених зниженням активності одного з 4 ферментів, залучених у процес послідовного розщеплення гепарансульфату [43][44][45]. Залежно від біохімічного дефекту виділяють 4 підтипи МПС ІІІ: А, B, C і D. У більшості (майже 70 % спостережень) хворих діагностований МПС ІІІ А (табл.…”