ADAR Expression and Single Nucleotide Variants in Multiple Sclerosis Patients Affect the Response to Interferon Beta Therapy.

Interferon (IFN)-ß is the first-line disease management choice in multiple sclerosis (MS) with profound effects; however, in up to 50% of patients, clinical response does not occur. Ascertaining the responding state, need a long-term clinical follow-up, and this may lead to delay in use of other effective medications. IFN-induced cascade and its regulation is considered to play a major role in MS. Adenosine deaminase, RNA-specific (ADAR) dysregulation is important to IFN signaling pathway as an activity suppressor. Hence, we investigated the expression of ADAR and its single nucleotide variants of rs2229857 association with response to IFN-ß in relapsing-remitting MS patients. mRNA levels and genotyping of rs2229857 in 167 MS patients were investigated via SYBR Green real-time (RT)-quantitative polymerase chain reaction and high-resolution melting RT PCR, respectively. The allele-A in rs2229857 and higher expression of ADAR were associated with poor response to IFN-ß. Two response groups were significantly different in terms of annualized relapse rate, first symptoms, first extended disability status scale (EDSS), current EDSS, and the MS severity score. According to this study's findings, assessment of transcript levels and also variants in ADAR may be useful in identifying patients' response to IFN-ß before starting treatment. Further investigations are needed to determine the potency of ADAR to be a predictive biomarker in drug responsiveness.

Griscelli syndrome type 1: a novel pathogenic variant, and review of literature.

Griscelli syndrome type 1 (GS1) is a rare inherited autosomal recessive disease caused by a deleterious variant in the MYO5A gene and characterized by general hypopigmentation, neurological symptoms, motor disability, hypotonia, and vision abnormality. Only nine pathogenic variants in the MYO5A gene have been confirmed in association with the GS1. All of the reported pathogenic variants are truncating. Herein, two siblings from a consanguineous Iranian family with abnormal pigmentation and neurological symptoms were referred for genetic counseling. Whole-exome sequencing (WES) revealed a novel homozygous truncating variant c.1633_1634delAA (p.Asn545Glnfs*10) in the MYO5A gene, which was completely co-segregated with the phenotype in all affected and unaffected family members. Computational analysis and protein modeling demonstrated the deleterious effects of this variant on the structure and function of the protein. The variant, according to ACMG guidelines, was classified as pathogenic. Besides the novelty of the identified variant, our patients manifested more severe clinical symptoms and presented distal hyperlaxity in all four limbs, which was a new finding. In conclusion, we expanded the mutational and phenotypic spectrum of the GS1. Moreover, by studying clinical manifestations in all molecularly confirmed reported cases, provided a comprehensive overview of clinical presentation, and attempted to find a genotype-phenotype correlation.

An interdependence between GAPVD1 gene polymorphism, expression level and response to interferon beta in patients with multiple sclerosis.

Interferon-ß (IFN-ß) is among the first drugs used for reducing the symptoms of multiple sclerosis (MS). Many studies show that the genetic predisposition of patients might modulate their response to IFN-ß treatment. In this study GAPVD1 gene expression and the genotyping of rs2291858 variant were analysed in 100 responder and 100 non-responder patients with MS treated using IFN-ß. Moreover, rs2291858 genotyping was performed for 200 patients with MS and 200 healthy controls. GAPVD1 expression was significantly increased in the responder patients than in non-responders and the distribution of rs2291858 polymorphism was significantly different between them. The GAPVD1 expression level in AA genotype of the responder group was higher than that in other genotypes of these two groups. The results show that the GAPVD1 expression level and rs2291858 genotype probably affect the response to IFN- ß in patients with MS.

A Novel Pathogenic Variant in NAGLU (N-Acetyl-Alpha-Glucosaminidase) gene Identified by Targeted Next-Generation Sequencing Followed by in Silico Analysis.

BACKGROUND: Mucopolysaccharidosis IIIB (MPS IIIB) (Sanfilippo Syndrome Type B; OMIM 252920) is an autosomal recessive metabolic disorder caused by mutations in the NAGLU gene which encode lysosomal enzyme N-acetyl-glucosaminidase, involved in degradation of complex polysaccharide, heparan sulfate. The disease is characterized by progressive cognitive decline and behavioral difficulties and motor function retardation. MATERIALS & METHODS: In this study, targeted exome sequencing was used in consanguineous parent (mother) of a deceased child with clinical diagnosis of mucopolysaccharidosis. Sanger sequencing was performed to confirm the candidate pathogenic variants in extended family members and segregation analysis. In silico pathogenicity assessment of detected variant using multiple computational predictive tools were performed. Computational docking using the Molegro Virtual Docker (MVD) 6.0.1 software applied to evaluate affinity binding of altered protein for its ligand, N-Acetyl-D-Glucosamine. Moreover, with I-TASSER software functional alterations between wild and mutant proteins evaluated. RESULTS: We identified a novel heterozygote deletion variant (c.1294-1304 del CTCTTCCCCAA, p.432LeufsX25) in the NAGLU gene. The variant was classified as pathogenic based on the American College of Medical Genetics and Genomics guideline. Computational docking with the Molegro Virtual Docker (MVD) 6.0.1 software confirmed different affinity binding of truncated protein for its ligand. Moreover, I-TASSER software revealed structural and functional alterations of mutant proteins. CONCLUSION: This study expands the spectrum of NAGLU pathogenic variants and confirms the utility of targeted NGS sequencing in genetic diagnosis and also the utility and power of additional family information.