Yoshihiro Matsudate1, Takuya Naruto2, Yumiko Hayashi3, Mitsuyoshi Minami4, Mikiko Tohyama5, Kenji Yokota6, Daisuke Yamada7, Issei Imoto2, Yoshiaki Kubo8. 1. Department of Dermatology, Tokushima University Graduate School of Medical Science, Tokushima, Japan. 2. Department of Human Genetics, Tokushima University Graduate School of Medical Science, Tokushima, Japan. 3. Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. 4. Divisions of Dermatology, Matsuyama Red Cross Hospital, Matsuyama, Japan. 5. Department of Dermatology, Ehime University Graduate School of Medicine, Ehime, Japan. 6. Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan. 7. Department of Dermatology, University of Tokyo Graduate School of Medicine, Tokyo, Japan. 8. Department of Dermatology, Tokushima University Graduate School of Medical Science, Tokushima, Japan. Electronic address: kubo@tokushima-u.ac.jp.
Abstract
BACKGROUND: Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder mainly caused by heterozygous mutations of PTCH1. In addition to characteristic clinical features, detection of a mutation in causative genes is reliable for the diagnosis of NBCCS; however, no mutations have been identified in some patients using conventional methods. OBJECTIVE: To improve the method for the molecular diagnosis of NBCCS. METHODS: We performed targeted exome sequencing (TES) analysis using a multi-gene panel, including PTCH1, PTCH2, SUFU, and other sonic hedgehog signaling pathway-related genes, based on next-generation sequencing (NGS) technology in 8 cases in whom possible causative mutations were not detected by previously performed conventional analysis and 2 recent cases of NBCCS. Subsequent analysis of gross deletion within or around PTCH1 detected by TES was performed using chromosomal microarray (CMA). RESULTS: Through TES analysis, specific single nucleotide variants or small indels of PTCH1 causing inferred amino acid changes were identified in 2 novel cases and 2 undiagnosed cases, whereas gross deletions within or around PTCH1, which are validated by CMA, were found in 3 undiagnosed cases. However, no mutations were detected even by TES in 3 cases. Among 3 cases with gross deletions of PTCH1, deletions containing the entire PTCH1 and additional neighboring genes were detected in 2 cases, one of which exhibited atypical clinical features, such as severe mental retardation, likely associated with genes located within the 4.3Mb deleted region, especially. CONCLUSION: TES-based simultaneous evaluation of sequences and copy number status in all targeted coding exons by NGS is likely to be more useful for the molecular diagnosis of NBCCS than conventional methods. CMA is recommended as a subsequent analysis for validation and detailed mapping of deleted regions, which may explain the atypical clinical features of NBCCS cases.
BACKGROUND:Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder mainly caused by heterozygous mutations of PTCH1. In addition to characteristic clinical features, detection of a mutation in causative genes is reliable for the diagnosis of NBCCS; however, no mutations have been identified in some patients using conventional methods. OBJECTIVE: To improve the method for the molecular diagnosis of NBCCS. METHODS: We performed targeted exome sequencing (TES) analysis using a multi-gene panel, including PTCH1, PTCH2, SUFU, and other sonic hedgehog signaling pathway-related genes, based on next-generation sequencing (NGS) technology in 8 cases in whom possible causative mutations were not detected by previously performed conventional analysis and 2 recent cases of NBCCS. Subsequent analysis of gross deletion within or around PTCH1 detected by TES was performed using chromosomal microarray (CMA). RESULTS: Through TES analysis, specific single nucleotide variants or small indels of PTCH1 causing inferred amino acid changes were identified in 2 novel cases and 2 undiagnosed cases, whereas gross deletions within or around PTCH1, which are validated by CMA, were found in 3 undiagnosed cases. However, no mutations were detected even by TES in 3 cases. Among 3 cases with gross deletions of PTCH1, deletions containing the entire PTCH1 and additional neighboring genes were detected in 2 cases, one of which exhibited atypical clinical features, such as severe mental retardation, likely associated with genes located within the 4.3Mb deleted region, especially. CONCLUSION:TES-based simultaneous evaluation of sequences and copy number status in all targeted coding exons by NGS is likely to be more useful for the molecular diagnosis of NBCCS than conventional methods. CMA is recommended as a subsequent analysis for validation and detailed mapping of deleted regions, which may explain the atypical clinical features of NBCCS cases.
Authors: D Matthew Gianferante; Melissa Rotunno; Michael Dean; Weiyin Zhou; Belynda D Hicks; Kathleen Wyatt; Kristine Jones; Mingyi Wang; Bin Zhu; Alisa M Goldstein; Lisa Mirabello Journal: Mol Genet Genomic Med Date: 2018-11-08 Impact factor: 2.183