Intronic OTOF mutation causes an atypical splicing defect resulting in auditory neuropathy spectrum disorder.

Pathogenic variants in OTOF cause auditory neuropathy spectrum disorder (ANSD), namely prelingual nonsyndromic ANSD and temperature-sensitive ANSD (TS-ANSD). All study subjects provided blood sample for genetic analysis and sequencing. Wholeexome sequencing was carried out to identify the causative pathogenic variant. RNAwas extracted to analyse the messenger RNA (mRNA) resulting from the transcription of OTOF. Here, we identified a family with OTOF-related ANSD. This disorder was caused by an intronic mutation in OTOF (NM_194248: c.2406>4A[G). In further analysis, we proved that this variant causes a splicing defect resulting in the omission of exon 20 from the mRNA transcribed from OTOF. In this study, we demonstrated that the variant is four nucleotides away from the conventional splicing site, and our findings suggest that splicing mechanisms need to be better understood, as well as how neighbouring regions may impact splicing.

Using CRISPR/Cas9 System to Knock out Exon 48 in DMD Gene.

BACKGROUND: Out of frame mutations in DMD gene cause Duchenne Muscular Dystrophy (DMD) which is a neuromuscular progressive genetic disorder. In DMD patients, lack of dystrophin causes progressive muscle degeneration, which results in heart and respiratory failure leading to premature death. At present, there is no certain treatment for DMD. DMD gene is the largest gene in human genome by 2.2 mega base pairs and contains 79 exons. In the past few years, gene therapy has been considered a promising DMD treatment, and among various gene-editing technologies, CRISPR/Cas9 system is shown to be more precise and reliable. The aim of this study was to assess the possibility of knocking out exon 48 by using a pair of sgRNAs. METHODS: A pair of guide RNAs (gRNAs) was designed to cleave DMD gene and induce deletion of exon 48. gRNAs were transfected to the HEK-293 cell line and then the deletion in genomic DNA was analyzed by PCR and subsequent Sanger sequencing. RESULTS: Exon 48 was successfully deleted and therefore exon 47 was joined to exon 49. CONCLUSION: This result indicated that CRISPR/Cas9 system could be used to edit DMD gene precisely.

First Case Report of EX3del4765 Mutation in PAH Gene in Asian Population.

INTRODUCTION: Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism, which is caused by mutation in phenylalanine hydroxylase (PAH) gene. Most of the PAH mutations are missense mutations (67%), which are followed by small or large deletions (13%). CASE PRESENTATION: We reported a patient with classic PKU and his parents harboring a large deletion in exon 3 (EX3del4765) of PAH gene. This is the first case report of EX3del4765 in Asian patients with PKU. CONCLUSIONS: This finding may help improve early detection, differential diagnosis, genetic counseling, and even treatment of patients with PKU.