Mucopolysaccharidosis type VI in the Russian registry: Further insights and considerations

This commentary evaluates the recent registry-based study of mucopolysaccharidosis type VI by Vechkasova et al, highlighting several methodological and reporting concerns that limit the interpretation of the findings. Although the establishment of a national registry is commendable and need of the time, the authors report an absence of correlations between clinical severity, age of onset, enzyme activity, and nucleotide variants without presenting any supporting statistical analyses or genotype-phenotype assessments. The dataset also appears affected by survivorship bias, and inconsistencies in reporting patient outcomes. Important clinical and genetic details, such as gender-stratified characteristics, variant zygosity and phasing, and American College of Medical Genetics and Genomics-based variant interpretation, are missing. Additionally, the use of inaccurate terminology and unclear prevalence calculations further complicates the interpretation. While the registry represents an important step toward understanding mucopolysaccharidosis type VI in Russia, improved methodological transparency, consistent terminology, and clearer data presentation are essential to strengthen the utility of these findings.