Innovative Nanopore Sequencing Assay Enhances Screening for Fragile X Syndrome Carriers

Researchers have introduced a groundbreaking nanopore sequencing method designed to improve the screening process for carriers of fragile X syndrome (FXS), which is the most prevalent cause of inherited intellectual disabilities and autism spectrum disorder. Published in The Journal of Molecular Diagnostics (2025), this study addresses the critical need for a more effective, rapid, and cost-efficient screening tool that surpasses existing techniques. The new assay enables comprehensive detection of FMR1 gene variations, including full mutations and premutations, which are vital for accurate carrier identification.

Fragile X syndrome affects approximately 1 in 7,000 females and 1 in 4,000 males across the globe. Its symptoms range from mild to severe intellectual disability, developmental delays, behavioral issues such as ADHD-like traits, autism spectrum disorder, sensory sensitivities, and distinctive physical features.

Lead researcher Dr. Qiwei Guo from Xiamen University explains that while FXS carrier prevalence is high across all ethnic groups, widespread population screening remains controversial. The research team developed a user-friendly software to analyze sequencing data efficiently, enabling the assessment of large numbers of female samples rapidly.

The FMR1 gene, responsible for FXS, is located on the X chromosome and contains CGG trinucleotide repeats which determine the gene's status—normal, premutation, or full mutation. The new nanopore assay accurately quantifies these repeats and detects AGG interruptions, DNA variations influential in mutation expansion risk, facilitating improved genetic counseling.

By employing barcode sequences, the assay can process multiple samples simultaneously, dramatically increasing capacity and reducing costs. It can deliver results within approximately two days for 100 samples in a standard molecular diagnostics lab. Its portability and affordability make it especially suitable for deployment in resource-limited settings.

Dr. Guo emphasizes that this advancement could significantly impact early diagnosis and intervention strategies, ultimately helping to reduce morbidity associated with FXS. The study demonstrates that this novel approach overcomes many limitations of traditional screening techniques, paving the way for broader implementation globally and enhancing genetic counseling for at-risk populations.

For more detailed information, the study by Zhongmin Xia et al., "Fragile X Syndrome Carrier Screening Using a Nanopore Sequencing Assay," is available in The Journal of Molecular Diagnostics (2025). Source: https://medicalxpress.com/news/2025-06-assay-efficient-screening-carriers-fragile.html