The diagnostic application of targeted re-sequencing in Korean patients with retinitis pigmentosa

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Abstract Background Identification of the causative genes of retinitis pigmentosa (RP) is important for the clinical care of patients with RP. However, a comprehensive genetic study has not been performed in Korean RP patients. Moreover, the genetic heterogeneity found in sensorineural genetic disorders makes identification of pathogenic mutations challenging. Therefore, high throughput genetic testing using massively parallel sequencing is needed. Results Sixty-two Korean patients with nonsyndromic RP (46 patients from 18 families and 16 simplex cases) who consented to molecular genetic testing were recruited in this study and targeted exome sequencing was applied on 53 RP-related genes. Causal variants were characterised by selecting exonic and splicing variants, selecting variants with low allele frequency (below 1 %), and discarding the remaining variants with quality below 20. The variants were additionally confirmed by an inheritance pattern and cosegregation test of the families, and the rest of the variants were prioritised using in-silico prediction tools. Finally, causal variants were detected from 10 of 18 familial cases (55.5 %) and 7 of 16 simplex cases (43.7 %) in total. Novel variants were detected in 13 of 20 (65 %) candidate variants. Compound heterozygous variants were found in four of 7 simplex cases. Conclusion Panel-based targeted re-sequencing can be used as an effective molecular diagnostic tool for RP

Efficacy of BRAF Inhibitors in Asian Metastatic Melanoma Patients: Potential Implications of Genomic Sequencing in BRAF-Mutated Melanoma

BACKGROUND: The BRAF inhibitors vemurafenib and dabrafenib are currently the standard treatment for metastatic melanoma with BRAF V600 mutations. However, given the rarity of noncutaneous melanoma, including acral and mucosal subtypes, the efficacy of BRAF inhibitors for this subset of patients has not been extensively investigated. Acquired resistance generally appears 6 to 8 months after treatment with a BRAF inhibitor, and the mechanism of resistance is not well established. METHODS: We examined treatment outcomes for patients diagnosed with metastatic melanoma and treated with BRAF inhibitors at Samsung Medical Center between April 2013 and December 2015. We analyzed genomic alterations in selected patients using targeted sequencing. RESULTS: Twenty-seven patients with a median age of 49 years (range 23-82 years) with metastatic melanoma and treated with a BRAF inhibitor were identified. Of these patients, 19 (70.3%) had noncutaneous melanoma, including acral and mucosal melanoma. All patients had BRAFV600E mutations. The median progression-free survival of all patients was 9.2 months (95% confidence interval, 1.6-16.7), and the objective response rate was 78.9% in the mucosal/acral melanoma group and 75.0% in the cutaneous melanoma group. Three (11.1%) patients achieved complete response, and 19 (70.4%) showed a partial response. Targeted sequencing in five patients demonstrated NF1 mutations in three patients who did not respond to BRAF inhibitors. CONCLUSION: BRAF inhibitors were an effective therapeutic option for Korean patients with metastatic melanoma harboring a BRAF V600 mutation regardless of melanoma subtype (acral/mucosa versus cutaneous)