Automated prediction of the clinical impact of structural copy number variations.

Copy number variants (CNVs) play an important role in many biological processes, including the development of genetic diseases, making them attractive targets for genetic analyses. The interpretation of the effect of these structural variants is a challenging problem due to highly variable numbers of gene, regulatory, or other genomic elements affected by the CNV. This led to the demand for the interpretation tools that would relieve researchers, laboratory diagnosticians, genetic counselors, and clinical geneticists from the laborious process of annotation and classification of CNVs. We designed and validated a prediction method (ISV; Interpretation of Structural Variants) that is based on boosted trees which takes into account annotations of CNVs from several publicly available databases. The presented approach achieved more than 98% prediction accuracy on both copy number loss and copy number gain variants while also allowing CNVs being assigned "uncertain" significance in predictions. We believe that ISV's prediction capability and explainability have a great potential to guide users to more precise interpretations and classifications of CNVs.

Targeted next-generation sequencing in Slovak cardiomyopathy patients.

OBJECTIVES: For the first time we used targeted next-generation sequencing to detect candidate pathogenic variants in Slovak cardiomyopathy patients. BACKGROUND: Targeted next-generation sequencing is considered to be the best practice in genetic diagnostics of cardiomyopathies. However, in Slovakia, with high cardiomyopathies prevalence of 1/440, the current diagnostic tests are still based on Sanger sequencing of a few genes. Consequently, little is known about the exact contribution of pathogenic variants in known cardiomyopathy genes in Slovak patients. METHODS: We used a panel of 46 known cardiomyopathy-associated genes to detect genetic variants in 16 Slovak cardiomyopathy patients (6 dilated, 8 hypertrophic, 2 non-compaction subtypes). RESULTS: We identified candidate pathogenic variants in 11 of 16 patients (69 %). Genes with higher count of candidate pathogenic variants were MYBPC3, MYH and TTN, each with 3 different variants. Seven variants ACTC1 (c.329C>T), ANKRD1 (c.683G>T), MYH7 (c.1025C>T), PKP2 (c.2003delA), TTN (c.51655C>T, c.84841G>T, c.101874_101881delAGAATTTG) have been detected for the first time and might represent Slovak-specific genetic cause. CONCLUSIONS: We have performed genetic testing of previously untested Slovak cardiomyopathy patients using next-generation sequencing cardiomyopathy gene panel. Given the high percentage of candidate pathogenic variants it should be recommended to implement this method into routine genetic diagnostic practice in Slovakia (Tab. 4, Ref. 39).

Complex phenotypes blur conventional borders between Say-Barber-Biesecker-Young-Simpson syndrome and genitopatellar syndrome.

Say-Barber-Biesecker-Young-Simpson syndrome (SBBYSS) and genitopatellar syndrome (GTPTS) are clinically similar disorders with some overlapping features. Although they are currently considered to be distinct clinical entities, both were found to be caused by de novo truncating sequence variants in the KAT6B (lysine acetyltransferase 6B) gene, strongly suggesting that they are allelic disorders. Herein, we report the clinical and genetic findings in a girl presenting with a serious multiple congenital anomaly syndrome with phenotypic features overlapping both SBBYSS and GTPTS; pointing out that the clinical distinction between these disorders is not exact and there do exist patients, in whom conventional clinical classification is problematic. Genetic analyses revealed a truncating c.4592delA (p.Asn1531Thrfs*18) variant in the last KAT6B exon. Our findings support that phenotypes associated with typical KAT6B disease-causing variants should be referred to as 'KAT6B spectrum disorders' or 'KAT6B related disorders', rather than their current SBBYSS and GTPTS classification.