TY - JOUR A1 - Vona, Barbara A1 - Maroofian, Reza A1 - Bellacchio, Emanuele A1 - Najafi, Maryam A1 - Thompson, Kyle A1 - Alahmad, Ahmad A1 - He, Langping A1 - Ahangari, Najmeh A1 - Rad, Abolfazl A1 - Shahrokhzadeh, Sima A1 - Bahena, Paulina A1 - Mittag, Falk A1 - Traub, Frank A1 - Movaffagh, Jebrail A1 - Amiri, Nafise A1 - Doosti, Mohammad A1 - Boostani, Reza A1 - Shirzadeh, Ebrahim A1 - Haaf, Thomas A1 - Diodato, Daria A1 - Schmidts, Miriam A1 - Taylor, Robert W. A1 - Karimiani, Ehsan Ghayoor T1 - Expanding the clinical phenotype of IARS2-related mitochondrial disease JF - BMC Medical Genetics N2 - Background: IARS2 encodes a mitochondrial isoleucyl-tRNA synthetase, a highly conserved nuclear-encoded enzyme required for the charging of tRNAs with their cognate amino acid for translation. Recently, pathogenic IARS2 variants have been identified in a number of patients presenting broad clinical phenotypes with autosomal recessive inheritance. These phenotypes range from Leigh and West syndrome to a new syndrome abbreviated CAGSSS that is characterised by cataracts, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss, and skeletal dysplasia, as well as cataract with no additional anomalies. Methods: Genomic DNA from Iranian probands from two families with consanguineous parental background and overlapping CAGSSS features were subjected to exome sequencing and bioinformatics analysis. Results: Exome sequencing and data analysis revealed a novel homozygous missense variant (c.2625C > T, p.Pro909Ser, NM_018060.3) within a 14.3 Mb run of homozygosity in proband 1 and a novel homozygous missense variant (c.2282A > G, p.His761Arg) residing in an ~ 8 Mb region of homozygosity in a proband of the second family. Patient-derived fibroblasts from proband 1 showed normal respiratory chain enzyme activity, as well as unchanged oxidative phosphorylation protein subunits and IARS2 levels. Homology modelling of the known and novel amino acid residue substitutions in IARS2 provided insight into the possible consequence of these variants on function and structure of the protein. Conclusions: This study further expands the phenotypic spectrum of IARS2 pathogenic variants to include two patients (patients 2 and 3) with cataract and skeletal dysplasia and no other features of CAGSSS to the possible presentation of the defects in IARS2. Additionally, this study suggests that adult patients with CAGSSS may manifest central adrenal insufficiency and type II esophageal achalasia and proposes that a variable sensorineural hearing loss onset, proportionate short stature, polyneuropathy, and mild dysmorphic features are possible, as seen in patient 1. Our findings support that even though biallelic IARS2 pathogenic variants can result in a distinctive, clinically recognisable phenotype in humans, it can also show a wide range of clinical presentation from severe pediatric neurological disorders of Leigh and West syndrome to both non-syndromic cataract and cataract accompanied by skeletal dysplasia. KW - adrenal insufficiency KW - CAGSSS KW - cataracts KW - growth hormone deficiency KW - IARS2 KW - sensory neuropathy KW - sensorineural hearing loss KW - type II esophageal achalasia KW - skeletal dysplasia Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176620 VL - 19 IS - 196 ER - TY - JOUR A1 - Vona, Barbara A1 - Hofrichter, Michaela A. H. A1 - Schröder, Jörg A1 - Shehata-Dieler, Wafaa A1 - Nanda, Indrajit A1 - Haaf, Thomas T1 - Hereditary hearing loss SNP-microarray pilot study JF - BMC Research Notes N2 - Objectives: Despite recent advancements in diagnostic tools, the genomic landscape of hereditary hearing loss remains largely uncharacterized. One strategy to understand genome-wide aberrations includes the analysis of copy number variation that can be mapped using SNP-microarray technology. A growing collection of literature has begun to uncover the importance of copy number variation in hereditary hearing loss. This pilot study underpins a larger effort that involves the stage-wise analysis of hearing loss patients, many of whom have advanced to high-throughput sequencing analysis. Data description: Our data originate from the Infinium HumanOmni1-Quad v1.0 SNP-microarrays (Illumina) that provide useful markers for genome-wide association studies and copy number variation analysis. This dataset comprises a cohort of 108 individuals (99 with hearing loss, 9 normal hearing family members) for the purpose of understanding the genetic contribution of copy number variations to hereditary hearing loss. These anonymized SNP-microarray data have been uploaded to the NCBI Gene Expression Omnibus and are intended to benefit other investigators interested in aggregating platform-matched array patient datasets or as part of a supporting reference tool for other laboratories to better understand recurring copy number variations in other genetic disorders. KW - copy number variation KW - genotyping arrays KW - hereditary hearing loss KW - illumina KW - infinium HumanOmni1-Quad KW - SNP-microarray Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176239 VL - 11 IS - 391 ER - TY - JOUR A1 - Hofrichter, Michaela A. H. A1 - Mojarad, Majid A1 - Doll, Julia A1 - Grimm, Clemens A1 - Eslahi, Atiye A1 - Hosseini, Neda Sadat A1 - Rajati, Mohsen A1 - Müller, Tobias A1 - Dittrich, Marcus A1 - Maroofian, Reza A1 - Haaf, Thomas A1 - Vona, Barbara T1 - The conserved p.Arg108 residue in S1PR2 (DFNB68) is fundamental for proper hearing: evidence from a consanguineous Iranian family JF - BMC Medical Genetics N2 - Background: Genetic heterogeneity and consanguineous marriages make recessive inherited hearing loss in Iran the second most common genetic disorder. Only two reported pathogenic variants (c.323G>C, p.Arg108Pro and c.419A>G, p.Tyr140Cys) in the S1PR2 gene have previously been linked to autosomal recessive hearing loss (DFNB68) in two Pakistani families. We describe a segregating novel homozygous c.323G>A, p.Arg108Gln pathogenic variant in S1PR2 that was identified in four affected individuals from a consanguineous five generation Iranian family. Methods: Whole exome sequencing and bioinformatics analysis of 116 hearing loss-associated genes was performed in an affected individual from a five generation Iranian family. Segregation analysis and 3D protein modeling of the p.Arg108 exchange was performed. Results: The two Pakistani families previously identified with S1PR2 pathogenic variants presented profound hearing loss that is also observed in the affected Iranian individuals described in the current study. Interestingly, we confirmed mixed hearing loss in one affected individual. 3D protein modeling suggests that the p.Arg108 position plays a key role in ligand receptor interaction, which is disturbed by the p.Arg108Gln change. Conclusion: In summary, we report the third overall mutation in S1PR2 and the first report outside the Pakistani population. Furthermore, we describe a novel variant that causes an amino acid exchange (p.Arg108Gln) in the same amino acid residue as one of the previously reported Pakistani families (p.Arg108Pro). This finding emphasizes the importance of the p.Arg108 amino acid in normal hearing and confirms and consolidates the role of S1PR2 in autosomal recessive hearing loss. KW - 3D modeling KW - autosomal recessive non-synstromic hearing loss KW - DFNB68 KW - mixed hearing loss KW - whole exome sequencing KW - S1PR2 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175755 VL - 19 IS - 81 ER -