Questioning the Clinical Utility of Exome Sequencing in Developing Countries

A systematic review of the assessment of the clinical utility of genomic sequencing: Implications of the lack of standard definitions and measures of clinical utility

PURPOSE

Exome sequencing (ES) and genome sequencing (GS) are diagnostic tests for rare genetic diseases. Studies report clinical utility of ES/GS. The goal of this systematic review is to establish how clinical utility is defined and measured in studies evaluating the impacts of ES/GS results for pediatric patients.

METHODS

Relevant articles were identified in PubMed, Medline, Embase, and Web of Science. Eligible studies assessed clinical utility of ES/GS for pediatric patients published before 2021. Other relevant articles were added based on articles' references. Articles were coded to assess definitions and measures of clinical utility.

RESULTS

Of 1346 articles, 83 articles met eligibility criteria. Clinical utility was not clearly defined in 19% of studies and 92% did not use an explicit measure of clinical utility. When present, definitions of clinical utility diverged from recommended definitions and varied greatly, from narrow (diagnostic yield of ES/GS) to broad (including decisions about withdrawal of care/palliative care and/or impacts on other family members).

CONCLUSION

Clinical utility is used to guide policy and practice decisions about test use. The lack of a standard definition of clinical utility of ES/GS may lead to under- or overestimations of clinical utility, complicating policymaking and raising ethical issues.

Whole-exome sequencing enables rapid and prenatal diagnosis of inherited skin disorders

BACKGROUND

Genodermatoses are a broad group of disorders with specific or non-specific skin-based phenotypes, most of which are monogenic disorders. However, it's a great challenge to make a precise molecular diagnosis because of the clinical heterogeneity. The genetic and clinical heterogeneity brings great challenges for diagnosis in dermatology. The whole exome sequencing (WES) not only expedites the discovery of the genetic variations, but also contributes to genetic counselling and prenatal diagnosis.

MATERIALS AND METHODS

Followed by the initial clinical and pathological diagnosis, genetic variations were identified by WES. The pathogenicity of the copy number variations (CNVs) and single-nucleotide variants (SNVs) were evaluated according to ACMG guidelines. Candidate pathogenic SNVs were confirmed by Sanger sequencing in the proband and the family members.

RESULTS

Totally 25 cases were recruited. Nine novel variations, including c.5546G > C and c.1457delC in NF1, c.6110G > T in COL7A1, c.2127delG in TSC1, c.1445 C > A and c.1265G > A in TYR, Xp22.31 deletion in STS, c.908 C > T in ATP2A2, c.1371insC in IKBKG, and nine known ones were identified in 16 cases (64%). Prenatal diagnosis was applied in 6 pregnant women by amniocentesis, two of whom carried positive findings.

CONCLUSIONS

Our findings highlighted the value of WES as a first-tier genetic test in determining the molecular diagnosis. We also discovered the distribution of genodermatoses in this district, which provided a novel clinical dataset for dermatologists.