Transcript Long-Read Sequencing Unveils the Molecular Complexity of a Novel ROGDI Splicing Variant in a Tunisian...

Area of Science:

• Genetics
• Molecular Biology
• Rare Diseases

Background:

• Kohlschütter-Tönz Syndrome (KTS) is an ultra-rare autosomal recessive disorder.
• KTS presents with infantile-onset epilepsy, global developmental delay, and amelogenesis imperfecta.
• Pathogenic variants in the ROGDI gene cause KTS, but its function remains largely unknown.

Purpose of the Study:

• To characterize a novel homozygous ROGDI variant identified in a Tunisian family with KTS.
• To investigate the molecular mechanisms underlying the ROGDI variant's impact on gene function.
• To explore potential therapeutic strategies for KTS.

Main Methods:

• Genetic analysis of a Tunisian family with KTS.
• Identification and characterization of a novel homozygous ROGDI variant (NM_024589.3:c.646-2A>G).
• Reverse-transcriptase polymerase chain reaction (RT-PCR) and targeted long-read cDNA sequencing to analyze ROGDI transcripts.

Main Results:

• The identified ROGDI variant disrupts a canonical acceptor splice site in intron 8.
• Complex splicing alterations, including exon skipping and cryptic splice site activation, were observed.
• These alterations lead to nonsense-mediated decay and predicted loss of ROGDI function.

Conclusions:

• The study elucidates the molecular basis of KTS caused by a novel ROGDI splice site variant.
• Understanding these complex splicing alterations provides critical insights into KTS pathogenesis.
• These findings may inform the development of future therapeutic interventions for KTS.