Genomic Newborn Screening: Advancing Towards Consensus and Implementation

Genomic newborn screening (gNBS) holds the promise of identifying treatable genetic diseases early in life, potentially preventing severe health consequences. But, establishing a standardized and effective gNBS program requires careful consideration of gene selection, diagnostic criteria, and program management. Recent advancements in genetic testing technologies, including DNA sequencing from dried blood spots (DBS), are making gNBS increasingly feasible. This article explores the evolving landscape of gNBS, focusing on the criteria for disease selection and the ongoing efforts to achieve international consensus.

The Need for Consensus in Gene Selection

Currently, gNBS gene lists vary considerably, despite shared principles of gene-disease validity, treatability, and age of onset. A study published in Genetics in Medicine identified 55 consensus genes included by all six gNBS research projects analyzed, highlighting areas of agreement but also discrepancies in approach. https://www.sciencedirect.com/science/article/pii/S1098360024000108 These discrepancies often stem from differing definitions of “treatability” and the strength of the gene-disease association.

Criteria for a Genomic Newborn Screening Program

A multi-dimensional framework for a gNBS program, developed by the NEW_LIVES project, consists of 18 screening criteria categorized into two overarching areas: transparent disease selection and program management. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/

A. Criteria Enabling Transparent Disease Selection

This category focuses on the characteristics of the target disease and the requirements of the test itself, encompassing four subcategories:

I. Clinical Criteria (Characteristics of the Target Disease)

• Gene-Disease Association: The association between the gene and the disease must be “definitive” or “strong” according to the ClinGen classification. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Penetrance: The penetrance of disease-associated variants should be at least 80%. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Severity: The target disease must be severe, resulting in premature death, major morbidity, or significantly impaired quality of life. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Age of Onset: The average age of onset should be less than 7 years. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/

II. Diagnostic Criteria (Requirements of the Test)

• Advantages over Existing Methods: gNBS should offer advantages over current diagnostic methods, such as increased reliability or earlier detection. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Molecular Genetic Identification: The disease must be clearly identifiable through molecular genetics with high sensitivity and specificity. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Variant Reporting: Only “likely pathogenic” and “pathogenic” variants, as classified by the American College of Medical Genetics and Genomics (ACMG), should be reported. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Confirmatory Testing: Suspected diagnoses from gNBS require confirmation through independent molecular genetic testing or established non-genetic diagnostic tests. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/

III. Therapeutic-Interventional Criteria (Prerequisites of the Intervention)

• Established Intervention: A therapeutic intervention with a demonstrably beneficial effect on the disease course must be available. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Early Intervention Feasibility: Pre- or early symptomatic intervention after gNBS identification must provide a health benefit compared to standard diagnosis. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/
• Benefit Outweighs Risk: The benefits of intervention must clearly outweigh the risks and burdens for the child. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082943/

B. Criteria to Establish, Manage, and Further Develop the gNBS Program

This category focuses on the operational aspects of the program, encompassing seven program management criteria, which should be met if the program is implemented on a population-wide level.

• Equal Access: Guarantee cost coverage for screening, diagnostics, and interventions.
• Voluntary Participation: Participation should remain voluntary with informed consent.
• Minimally Invasive Sample Collection: Utilize existing dried blood spot samples.
• Defined Procedures: Establish clear guidelines for sample collection, analysis, and follow-up.
• Data Protection: Adhere to strict data protection laws.
• Program Evaluation: Implement data-driven evaluation and quality assurance measures.
• Integrated and Learning Program: Establish central coordination and continuous re-evaluation.

Looking Ahead

The development of a consensus gene list and the implementation of robust screening criteria are crucial steps toward realizing the full potential of gNBS. Ongoing research, international collaboration, and ethical considerations will continue to shape the future of this promising technology, ultimately aiming to improve the health and well-being of newborns worldwide.