Shariant platform: Enabling evidence sharing across Australian clinical genetic-testing laboratories to support variant interpretation.

Sharing genomic variant interpretations across laboratories promotes consistency in variant assertions. A landscape analysis of Australian clinical genetic-testing laboratories in 2017 identified that, despite the national-accreditation-body recommendations encouraging laboratories to submit genotypic data to clinical databases, fewer than 300 variants had been shared to the ClinVar public database. Consultations with Australian laboratories identified resource constraints limiting routine application of manual processes, consent issues, and differences in interpretation systems as barriers to sharing. This information was used to define key needs and solutions required to enable national sharing of variant interpretations. The Shariant platform, using both the GRCh37 and GRCh38 genome builds, was developed to enable ongoing sharing of variant interpretations and associated evidence between Australian clinical genetic-testing laboratories. Where possible, two-way automated sharing was implemented so that disruption to laboratory workflows would be minimized. Terms of use were developed through consultation and currently restrict access to Australian clinical genetic-testing laboratories. Shariant was designed to store and compare structured evidence, to promote and record resolution of inter-laboratory classification discrepancies, and to streamline the submission of variant assertions to ClinVar. As of December 2021, more than 14,000 largely prospectively curated variant records from 11 participating laboratories have been shared. Discrepant classifications have been identified for 11% (28/260) of variants submitted by more than one laboratory. We have demonstrated that co-design with clinical laboratories is vital to developing and implementing a national variant-interpretation sharing effort. This approach has improved inter-laboratory concordance and enabled opportunities to standardize interpretation practices.

Ovarian Microcystic Stromal Tumor: A Rare Clinical Manifestation of Familial Adenomatous Polyposis.

Microcystic stromal tumor (MST) is a rare tumor of presumed sex-cord stromal differentiation. We present a case of MST arising within a patient with constitutional 5q deletion syndrome, whose deletion encompassed the APC gene. Genomic analysis of the MST revealed a point mutation in the remaining APC allele, predicted to result in abnormal splicing of Exon 7. Subsequent clinical investigation revealed multiple gastrointestinal polyps qualifying for a diagnosis of familial adenomatous polyposis. This case emphasizes the importance of an aberrant Wnt/ß-catenin pathway in the development of MST and adds credence to the inclusion of MST as a rare phenotype of familial adenomatous polyposis. In a search for additional genetic aberrations which may contribute to the development of this rare tumor, genomic analysis revealed a frameshift mutation in FANCD2, a protein which plays a key role in DNA repair. This protein is expressed in human ovarian stromal cells and FANCD2-knockout mice are known to develop sex cord-stromal tumors, factors which further support a possible role of aberrant FANCD2 in the development of MST.