Scholarlink

Background <p>Biallelic pathogenic variants in the <i>GALNS</i> gene lead to Mucopolysaccharidosis Type IVA (MPS IVA), a rare lysosomal storage disorder. <i>GALNS</i> encodes the enzyme N-acetylgalactosamine-6-sulfatase, whose deficiency causes accumulation of glycosaminoglycans and leads to a broad spectrum of clinical manifestations primarily affecting the osteoarticular system. Several studies have shown that, in 10%–15% of patients with the biochemical phenotype of MPS IVA, standard molecular genetic testing fails to identify one or both causative variants in the <i>GALNS</i> gene.</p> Methods <p>We performed an in-depth investigation of <i>GALNS’</i> splicing, with a special focus on deep-intronic mutations that lead to activation of pseudoexons (PEs). Using bioinformatic tools, we analyzed all deep-intronic variants in <i>GALNS</i> available in public databases and subjected the most relevant ones to in vitro analyses using minigenes.</p> Results <p>We characterized eight PE-activating variants, one of which (c.121-210C &gt; T) represents a recurrent pathogenic variant which has long been hidden behind the mask of a polymorphic variant. In addition, we demonstrate that <i>GALNS’</i> splicing can produce a diverse range of mRNA isoforms containing so-called wild-type PEs, which are present at low levels as part of non-productive splicing, and weak canonical exons which are prone to skipping. We show that PE-activating variants cluster within wild-type PEs, highlighting the need for closer scrutiny of these regions during genetic testing.</p> <p>Finally, we applied modified U7 small nuclear RNAs and circular RNAs to efficiently block the identified PEs and pave the way for personalized antisense-based therapy for MPS IVA patients.</p> Conclusion <p>The results of this study expand the understanding of <i>GALNS</i> gene splicing, indicating hotspots for splicing mutations. The presented data not only help to increase the diagnostic yield for MPS IVA but also unveil new therapeutic approaches for a number of MPS IVA patients.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Clinically relevant pseudoexons of the GALNS gene and their antisense-based correction

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年5月17日

查看全文
  • Igor Bychkov,
  • Elza Shchukina,
  • Ekaterina Zakharova

摘要

Background

Biallelic pathogenic variants in the GALNS gene lead to Mucopolysaccharidosis Type IVA (MPS IVA), a rare lysosomal storage disorder. GALNS encodes the enzyme N-acetylgalactosamine-6-sulfatase, whose deficiency causes accumulation of glycosaminoglycans and leads to a broad spectrum of clinical manifestations primarily affecting the osteoarticular system. Several studies have shown that, in 10%–15% of patients with the biochemical phenotype of MPS IVA, standard molecular genetic testing fails to identify one or both causative variants in the GALNS gene.

Methods

We performed an in-depth investigation of GALNS’ splicing, with a special focus on deep-intronic mutations that lead to activation of pseudoexons (PEs). Using bioinformatic tools, we analyzed all deep-intronic variants in GALNS available in public databases and subjected the most relevant ones to in vitro analyses using minigenes.

Results

We characterized eight PE-activating variants, one of which (c.121-210C > T) represents a recurrent pathogenic variant which has long been hidden behind the mask of a polymorphic variant. In addition, we demonstrate that GALNS’ splicing can produce a diverse range of mRNA isoforms containing so-called wild-type PEs, which are present at low levels as part of non-productive splicing, and weak canonical exons which are prone to skipping. We show that PE-activating variants cluster within wild-type PEs, highlighting the need for closer scrutiny of these regions during genetic testing.

Finally, we applied modified U7 small nuclear RNAs and circular RNAs to efficiently block the identified PEs and pave the way for personalized antisense-based therapy for MPS IVA patients.

Conclusion

The results of this study expand the understanding of GALNS gene splicing, indicating hotspots for splicing mutations. The presented data not only help to increase the diagnostic yield for MPS IVA but also unveil new therapeutic approaches for a number of MPS IVA patients.