76
|
InanlooRahatloo K, Peymani F, Kahrizi K, Najmabadi H. Whole-Transcriptome Analysis Reveals Dysregulation of Actin-Cytoskeleton Pathway in Intellectual Disability Patients. Neuroscience 2019; 404:423-444. [PMID: 30742961 DOI: 10.1016/j.neuroscience.2019.01.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 01/07/2019] [Accepted: 01/17/2019] [Indexed: 12/14/2022]
Abstract
A significant level of genetic heterogeneity has been demonstrated in intellectual disability (ID). More than 700 genes have been identified in ID patients. To identify molecular pathways underlying this heterogeneity, we applied whole-transcriptome analysis using RNA-Seq in consanguineous families with ID. Significant changes in expression of genes related to neuronal and actin cytoskeletal functions were observed in all the ID families. Remarkably, we found a significant down-regulation of SHTN1 gene and up-regulation of FGFR2 gene in all ID patients. FGFR2, but not SHTN1, was previously reported as an ID causing gene. Detailed gene ontology analyses identified pathways linked to tyrosine protein kinase, actin cytoskeleton, and axonogenesis to be affected in ID patients. The findings reported here provide new insights into the candidate genes and molecular pathways underling ID and highlight the key role of actin cytoskeleton in etiology of ID.
Collapse
|
77
|
Mehregan H, Mohseni M, Jalalvand K, Arzhangi S, Nikzat N, Banihashemi S, Kahrizi K, Najmabadi H. Novel mutations in MYTH4-FERM domains of myosin 15 are associated with autosomal recessive nonsyndromic hearing loss. Int J Pediatr Otorhinolaryngol 2019; 117:115-126. [PMID: 30579064 DOI: 10.1016/j.ijporl.2018.11.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 11/20/2018] [Accepted: 11/20/2018] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Hereditary hearing loss is the most common neurosensory disorder in humans caused by myriad mutations in numerous genes. Autosomal recessive nonsyndromic hearing loss (ARNSHL) accounts for 80% of hearing impairments of genetic origin and is quite prevalent in societies with a high rate of consanguinity. In the current study, we investigated the causes of sensorineural hearing loss in 24 unrelated Iranian families who were mainly consanguineous and had at least two affected children. METHODS All probands were initially screened for GJB2 mutations, as the most common causes of ARNSHL in Iran. Verified GJB2-negative samples were subsequently subjected to whole exome sequencing (WES) to identify the underlying causes of hearing impairment, and the variants identified in each family were further confirmed by Sanger sequencing. RESULTS WES revealed three previously unreported mutations in MYO15A, the gene encoding the unconventional myosin 15 (Myo15). All variants identified, c.C6436T (p.R2146W), c.C9584G (p.P3195R) and c.G10266C (p.Q3422H), reside in the MYTH4 (myosin tail homology) and FERM (4.1 ezrin, radixin, moesin) domains of the protein. CONCLUSION Globally, mutations in MYO15A are considered to be among the most prevalent genetic causes of ARNSHL, and they rank as the third leading cause of hearing loss in the Iranian population, below GJB2 and SLC26A4. Yet again, these results endorse the importance of MYO15 screening in hearing impaired populations, particularly in Iran.
Collapse
|
78
|
Fazeli Z, Ghaderian SMH, Najmabadi H, Omrani MD. High expression of miR-510 was associated with CGG expansion located at upstream of FMR1 into full mutation. J Cell Biochem 2019; 120:1916-1923. [PMID: 30160796 DOI: 10.1002/jcb.27505] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 08/20/2018] [Indexed: 01/24/2023]
Abstract
MicroRNAs (miRNAs) have been found to play an important role in the regulation of gene expression in eukaryotic organisms at the posttranscriptional level. More than half of miRNA genes have been recognized to be located in different fragile sites. Among them, miR-510 was located on chromosome X in the 27.3Xq region, flanking to a fragile X site. The CGG expansion and its methylation at the promoter of FMR1 located in this fragile site were associated with clinical symptoms of fragile X syndrome (FXS). The aim of the current study was to investigate whether the miR-510 expression was correlated with the CGG expansion of FMR1 in female carriers of full mutation. For this purpose, mesenchymal stem cells were isolated from peripheral blood of FMR1 full mutation female carriers. After differentiation of these cells into neuronal cells, the expression of miR-510 was analyzed by quantitative polymerase chain reaction. Furthermore, the target genes of miR-510 in the nervous system were also predicted by in silico method. The obtained results indicated that the CGG expansion of FMR1 was associated with the enhanced expression of miR-510. Furthermore, the bioinformatics analysis suggested that VHL and PPP2R5E genes could be considered as the most important target genes of miR-510 in the nervous system. This study showed that miR-510 and its target genes, specifically VHL and PPP2R5E, may represent the new targets for future therapy options of FXS.
Collapse
|
79
|
Imtiaz A, Belyantseva IA, Beirl AJ, Fenollar-Ferrer C, Bashir R, Bukhari I, Bouzid A, Shaukat U, Azaiez H, Booth KT, Kahrizi K, Najmabadi H, Maqsood A, Wilson EA, Fitzgerald TS, Tlili A, Olszewski R, Lund M, Chaudhry T, Rehman AU, Starost MF, Waryah AM, Hoa M, Dong L, Morell RJ, Smith RJH, Riazuddin S, Masmoudi S, Kindt KS, Naz S, Friedman TB. CDC14A phosphatase is essential for hearing and male fertility in mouse and human. Hum Mol Genet 2019; 27:780-798. [PMID: 29293958 DOI: 10.1093/hmg/ddx440] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/21/2017] [Indexed: 12/31/2022] Open
Abstract
The Cell Division-Cycle-14 gene encodes a dual-specificity phosphatase necessary in yeast for exit from mitosis. Numerous disparate roles of vertebrate Cell Division-Cycle-14 (CDC14A) have been proposed largely based on studies of cultured cancer cells in vitro. The in vivo functions of vertebrate CDC14A are largely unknown. We generated and analyzed mutations of zebrafish and mouse CDC14A, developed a computational structural model of human CDC14A protein and report four novel truncating and three missense alleles of CDC14A in human families segregating progressive, moderate-to-profound deafness. In five of these families segregating pathogenic variants of CDC14A, deaf males are infertile, while deaf females are fertile. Several recessive mutations of mouse Cdc14a, including a CRISPR/Cas9-edited phosphatase-dead p.C278S substitution, result in substantial perinatal lethality, but survivors recapitulate the human phenotype of deafness and male infertility. CDC14A protein localizes to inner ear hair cell kinocilia, basal bodies and sound-transducing stereocilia. Auditory hair cells of postnatal Cdc14a mutants develop normally, but subsequently degenerate causing deafness. Kinocilia of germ-line mutants of mouse and zebrafish have normal lengths, which does not recapitulate the published cdc14aa knockdown morphant phenotype of short kinocilia. In mutant male mice, degeneration of seminiferous tubules and spermiation defects result in low sperm count, and abnormal sperm motility and morphology. These findings for the first time define a new monogenic syndrome of deafness and male infertility revealing an absolute requirement in vivo of vertebrate CDC14A phosphatase activity for hearing and male fertility.
Collapse
|
80
|
Hosseini M, Fattahi Z, Abedini SS, Hu H, Ropers H, Kalscheuer VM, Najmabadi H, Kahrizi K. GPR126
: A novel candidate gene implicated in autosomal recessive intellectual disability. Am J Med Genet A 2018; 179:13-19. [DOI: 10.1002/ajmg.a.40531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 07/29/2018] [Accepted: 08/10/2018] [Indexed: 12/15/2022]
|
81
|
Kazeminasab S, Taskiran II, Fattahi Z, Bazazzadegan N, Hosseini M, Rahimi M, Oladnabi M, Haddadi M, Celik A, Ropers HH, Najmabadi H, Kahrizi K. CNKSR1 gene defect can cause syndromic autosomal recessive intellectual disability. Am J Med Genet B Neuropsychiatr Genet 2018; 177:691-699. [PMID: 30450701 DOI: 10.1002/ajmg.b.32648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The advent of high-throughput sequencing technologies has led to an exponential increase in the identification of novel disease-causing genes in highly heterogeneous diseases. A novel frameshift mutation in CNKSR1 gene was detected by Next-Generation Sequencing (NGS) in an Iranian family with syndromic autosomal recessive intellectual disability (ARID). CNKSR1 encodes a connector enhancer of kinase suppressor of Ras 1, which acts as a scaffold component for receptor tyrosine kinase in mitogen-activated protein kinase (MAPK) cascades. CNKSR1 interacts with proteins which have already been shown to be associated with intellectual disability (ID) in the MAPK signaling pathway and promotes cell migration through RhoA-mediated c-Jun N-terminal kinase (JNK) activation. Lack of CNKSR1 transcripts and protein was observed in lymphoblastoid cells derived from affected patients using qRT-PCR and western blot analysis, respectively. Furthermore, RNAi-mediated knockdown of cnk, the CNKSR1 orthologue in Drosophila melanogaster brain, led to defects in eye and mushroom body (MB) structures. In conclusion, our findings support the possible role of CNKSR1 in brain development which can lead to cognitive impairment.
Collapse
|
82
|
Kahrizi K, Hu H, Hosseini M, Kalscheuer VM, Fattahi Z, Beheshtian M, Suckow V, Mohseni M, Lipkowitz B, Mehvari S, Mehrjoo Z, Akhtarkhavari T, Ghaderi Z, Rahimi M, Arzhangi S, Jamali P, Falahat Chian M, Nikuei P, Sabbagh Kermani F, Sadeghinia F, Jazayeri R, Tonekaboni SH, Khoshaeen A, Habibi H, Pourfatemi F, Mojahedi F, Khodaie-Ardakani MR, Najafipour R, Wienker TF, Najmabadi H, Ropers HH. Effect of inbreeding on intellectual disability revisited by trio sequencing. Clin Genet 2018; 95:151-159. [PMID: 30315573 DOI: 10.1111/cge.13463] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 12/24/2022]
Abstract
In outbred Western populations, most individuals with intellectual disability (ID) are sporadic cases, dominant de novo mutations (DNM) are frequent, and autosomal recessive ID (ARID) is very rare. Because of the high rate of parental consanguinity, which raises the risk for ARID and other recessive disorders, the prevalence of ID is significantly higher in near- and middle-east countries. Indeed, homozygosity mapping and sequencing in consanguineous families have already identified a plethora of ARID genes, but because of the design of these studies, DNMs could not be systematically assessed, and the proportion of cases that are potentially preventable by avoiding consanguineous marriages or through carrier testing is hitherto unknown. This prompted us to perform whole-exome sequencing in 100 sporadic ID patients from Iran and their healthy consanguineous parents. In 61 patients, we identified apparently causative changes in known ID genes. Of these, 44 were homozygous recessive and 17 dominant DNMs. Assuming that the DNM rate is stable, these results suggest that parental consanguinity raises the ID risk about 3.6-fold, and about 4.1 to 4.25-fold for children of first-cousin unions. These results do not rhyme with recent opinions that consanguinity-related health risks are generally small and have been "overstated" in the past.
Collapse
|
83
|
Abedini SS, Forouzesh Pour F, Karimi K, Ghaderi Z, Farashi S, Tavakoli Koudehi A, Javadi Pirouz H, Mobini Nejad SB, Azarkeivan A, Najmabadi H. Frequency of α-Globin Gene Triplications and Coinheritance with β-Globin Gene Mutations in the Iranian Population. Hemoglobin 2018; 42:252-256. [PMID: 30451045 DOI: 10.1080/03630269.2018.1526192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Numerical variation in α-globin genes is very important due to their roles as an effective factor for phenotype presentation. An unequal crossover from misalignment of a homologous sequence of an α-globin gene during meiosis can produce a numerical alteration. A single α-globin gene deletion is the most frequent mutation in α-thalassemia (α-thal) worldwide, while the additional α-globin chain is relatively common. The excess α-globin gene plays a critical role in pathophysiology of thalassemia, especially when in coinherited with β-thalassemia (β-thal). α-Globin triplication leads to an imbalanced ratio between α- and β-globin chains, thus, it can exacerbate the clinical and hematological features of β-thal. Different studies have been performed in various countries to determine the frequency of α-globin triplication and its genotype-phenotype correlation with β-thal. In this study, we focused on the frequency of α-globin gene triplication and its characterization, either solely or in coexistence with β-globin gene mutations in Iranian populations. We have investigated the α-globin gene rearrangements in 4010 individuals from different provinces of Iran with normal to abnormal hematological parameters. In total, the frequency of the αααanti 3.7 triplication was 1.7% and phenotype aggravation was observed in α-globin triplication patients who were carriers of β-thal. Therefore, identification of genotype-phenotype correlation of α-globin triplication with β-thal can be very useful for predicting the severity of clinical manifestations during genetic counseling.
Collapse
|
84
|
Abedini SS, Kahrizi K, de Pouplana LR, Najmabadi H. tRNA Methyltransferase Defects and Intellectual Disability. ARCHIVES OF IRANIAN MEDICINE 2018; 21:478-485. [PMID: 30415557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/30/2018] [Indexed: 06/09/2023]
Abstract
In all organisms, transfer RNA (tRNA) molecules are required to undergo post-transcriptional modifications at different levels in order to convert into mature tRNAs. These modifications are critical for many aspects of tRNA function and structure, such as translational efficiency, flexibility, codon-anticodon interaction, stability, and fidelity. Up to now, over 100 modified nucleosides have been identified in tRNAs from all domains of life. Post-transcriptional modifications include different chemical processes such as methylation, deamination, or acetylation, with methylation reactions as the most common. tRNA methyltransferases are a family of enzymes involved in the post-transcriptional methylation of tRNA bases. Recent studies have reported different human diseases resulting from defects in tRNA methyltransferase activity, including cancer, diabetes and neurological disorders such as intellectual disability (ID). In this article, we focused on biological function and characterization of tRNA methyltransferases associated with ID in order to explain how functional disruption of tRNA methyltransferases could lead to ID phenotype.
Collapse
|
85
|
Avenarius MR, Jung JY, Askew C, Jones SM, Hunker KL, Azaiez H, Rehman AU, Schraders M, Najmabadi H, Kremer H, Smith RJH, Géléoc GSG, Dolan DF, Raphael Y, Kohrman DC. Grxcr2 is required for stereocilia morphogenesis in the cochlea. PLoS One 2018; 13:e0201713. [PMID: 30157177 PMCID: PMC6114524 DOI: 10.1371/journal.pone.0201713] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/22/2018] [Indexed: 11/18/2022] Open
Abstract
Hearing and balance depend upon the precise morphogenesis and mechanosensory function of stereocilia, the specialized structures on the apical surface of sensory hair cells in the inner ear. Previous studies of Grxcr1 mutant mice indicated a critical role for this gene in control of stereocilia dimensions during development. In this study, we analyzed expression of the paralog Grxcr2 in the mouse and evaluated auditory and vestibular function of strains carrying targeted mutations of the gene. Peak expression of Grxcr2 occurs during early postnatal development of the inner ear and GRXCR2 is localized to stereocilia in both the cochlea and in vestibular organs. Homozygous Grxcr2 deletion mutants exhibit significant hearing loss by 3 weeks of age that is associated with developmental defects in stereocilia bundle orientation and organization. Despite these bundle defects, the mechanotransduction apparatus assembles in relatively normal fashion as determined by whole cell electrophysiological evaluation and FM1-43 uptake. Although Grxcr2 mutants do not exhibit overt vestibular dysfunction, evaluation of vestibular evoked potentials revealed subtle defects of the mutants in response to linear accelerations. In addition, reduced Grxcr2 expression in a hypomorphic mutant strain is associated with progressive hearing loss and bundle defects. The stereocilia localization of GRXCR2, together with the bundle pathologies observed in the mutants, indicate that GRXCR2 plays an intrinsic role in bundle orientation, organization, and sensory function in the inner ear during development and at maturity.
Collapse
|
86
|
Charzewska A, Maiwald R, Kahrizi K, Oehl-Jaschkowitz B, Dufke A, Lemke J, Enders H, Najmabadi H, Tzschach A, Hachmann W, Jensen C, Bienek M, Poznański J, Nawara M, Chilarska T, Obersztyn E, Hoffman-Zacharska D, Gos M, Bal J, Kalscheuer V. The power of the Mediator complex-Expanding the genetic architecture and phenotypic spectrum of MED12
-related disorders. Clin Genet 2018; 94:450-456. [DOI: 10.1111/cge.13412] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/27/2018] [Accepted: 07/03/2018] [Indexed: 01/22/2023]
|
87
|
Booth KT, Kahrizi K, Najmabadi H, Azaiez H, Smith RJ. Old gene, new phenotype: splice-altering variants in CEACAM16 cause recessive non-syndromic hearing impairment. J Med Genet 2018; 55:555-560. [PMID: 29703829 PMCID: PMC6060001 DOI: 10.1136/jmedgenet-2018-105349] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/03/2018] [Accepted: 04/07/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND Hearing loss is a genetically and phenotypically heterogeneous disorder. OBJECTIVES The purpose of this study was to determine the genetic cause underlying the postlingual progressive hearing loss in two Iranian families. METHODS We used OtoSCOPE, a next-generation sequencing platform targeting >150 genes causally linked to deafness, to screen two deaf probands. Data analysis was completed using a custom bioinformatics pipeline, and variants were functionally assessed using minigene splicing assays. RESULTS We identified two homozygous splice-altering variants (c.37G>T and c.662-1G>C) in the CEACAM16 gene, segregating with the deafness in each family. The minigene splicing results revealed the c.37G>T results in complete skipping of exon 2 and loss of the AUG start site. The c.662-1G>C activates a cryptic splice site inside exon 5 resulting in a shift in the mRNA reading frame. CONCLUSIONS These results suggest that loss-of-function mutations in CEACAM16 result in postlingual progressive hearing impairment and further support the role of CEACAM16 in auditory function.
Collapse
|
88
|
Michel V, Booth KT, Patni P, Cortese M, Azaiez H, Bahloul A, Kahrizi K, Labbé M, Emptoz A, Lelli A, Dégardin J, Dupont T, Aghaie A, Oficjalska-Pham D, Picaud S, Najmabadi H, Smith RJ, Bowl MR, Brown SD, Avan P, Petit C, El-Amraoui A. CIB2, defective in isolated deafness, is key for auditory hair cell mechanotransduction and survival. EMBO Mol Med 2018; 9:1711-1731. [PMID: 29084757 PMCID: PMC5709726 DOI: 10.15252/emmm.201708087] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Defects of CIB2, calcium‐ and integrin‐binding protein 2, have been reported to cause isolated deafness, DFNB48 and Usher syndrome type‐IJ, characterized by congenital profound deafness, balance defects and blindness. We report here two new nonsense mutations (pGln12* and pTyr110*) in CIB2 patients displaying nonsyndromic profound hearing loss, with no evidence of vestibular or retinal dysfunction. Also, the generated CIB2−/− mice display an early onset profound deafness and have normal balance and retinal functions. In these mice, the mechanoelectrical transduction currents are totally abolished in the auditory hair cells, whilst they remain unchanged in the vestibular hair cells. The hair bundle morphological abnormalities of CIB2−/− mice, unlike those of mice defective for the other five known USH1 proteins, begin only after birth and lead to regression of the stereocilia and rapid hair‐cell death. This essential role of CIB2 in mechanotransduction and cell survival that, we show, is restricted to the cochlea, probably accounts for the presence in CIB2−/− mice and CIB2 patients, unlike in Usher syndrome, of isolated hearing loss without balance and vision deficits.
Collapse
|
89
|
Nozari A, Aghaei-Moghadam E, Zeinaloo A, Mollazadeh R, Majnoon MT, Alavi A, Ghasemi Firouzabadi S, Mohammadzadeh A, Banihashemi S, Nikzaban M, Najmabadi H, Behjati F. A novel splicing variant in FLNC gene responsible for a highly penetrant familial dilated cardiomyopathy in an extended Iranian family. Gene 2018; 659:160-167. [DOI: 10.1016/j.gene.2018.03.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 02/28/2018] [Accepted: 03/15/2018] [Indexed: 10/17/2022]
|
90
|
Hosseini M, Najmabadi H, Kahrizi K. Calpains: Diverse Functions but Enigmatic. ARCHIVES OF IRANIAN MEDICINE 2018; 21:170-179. [PMID: 29693408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/10/2018] [Indexed: 06/08/2023]
Abstract
Calpains are a group of non-lysosomal Ca2+-dependent cysteine proteases with numerous substrates. Calpains have been identified in almost all eukaryotes and bacteria but not in archaebacteria. In the human genome, this group of enzymes has 15 isoforms and is present ubiquitously and demonstrates tissue-specific patterns of expression. Calpains are involved in different physiological and pathological processes such as cell proliferation, migration, invasion, apoptosis and signal transduction and their roles in various disorders have been reported. In this review, functions of calpains, their substrates, their mechanism of regulation and their involvement in diseases have been summarized.
Collapse
|
91
|
Booth KT, Kahrizi K, Babanejad M, Daghagh H, Bademci G, Arzhangi S, Zareabdollahi D, Duman D, El-Amraoui A, Tekin M, Najmabadi H, Azaiez H, Smith RJ. Variants in CIB2 cause DFNB48 and not USH1J. Clin Genet 2018; 93:812-821. [PMID: 29112224 PMCID: PMC5851821 DOI: 10.1111/cge.13170] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 10/31/2017] [Accepted: 11/02/2017] [Indexed: 12/16/2022]
Abstract
The genetic, mutational and phenotypic spectrum of deafness-causing genes shows great diversity and pleiotropy. The best examples are the group of genes, which when mutated can either cause non-syndromic hearing loss (NSHL) or the most common dual sensory impairment, Usher syndrome (USH). Variants in the CIB2 gene have been previously reported to cause hearing loss at the DFNB48 locus and deaf-blindness at the USH1J locus. In this study, we characterize the phenotypic spectrum in a multiethnic cohort with autosomal recessive non-syndromic hearing loss (ARNSHL) due to variants in the CIB2 gene. Of the 6 families we ascertained, 3 segregated novel loss-of-function (LOF) variants, 2 families segregated missense variants (1 novel) and 1 family segregated a previously reported pathogenic variant in trans with a frameshift variant. This report is the first to show that biallelic LOF variants in CIB2 cause ARNSHL and not USH. In the era of precision medicine, providing the correct diagnosis (NSHL vs USH) is essential for patient care as it impacts potential intervention and prevention options for patients. Here, we provide evidence disqualifying CIB2 as an USH-causing gene.
Collapse
|
92
|
Booth KT, Azaiez H, Kahrizi K, Wang D, Zhang Y, Frees K, Nishimura C, Najmabadi H, Smith RJ. Exonic mutations and exon skipping: Lessons learned from DFNA5. Hum Mutat 2018; 39:433-440. [PMID: 29266521 PMCID: PMC5805621 DOI: 10.1002/humu.23384] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/27/2017] [Accepted: 12/12/2017] [Indexed: 02/06/2023]
Abstract
Dysregulation of splicing is a common factor underlying many inherited diseases including deafness. For one deafness-associated gene, DFNA5, perturbation of exon 8 splicing results in a constitutively active truncated protein. To date, only intronic mutations have been reported to cause exon 8 skipping in patients with DFNA5-related deafness. In five families with postlingual progressive autosomal dominant non-syndromic hearing loss, we employed two next-generation sequencing platforms-OtoSCOPE and whole exome sequencing-followed by variant filtering and prioritization based on both minor allele frequency and functional consequence using a customized bioinformatics pipeline to identify three novel and two recurrent mutations in DFNA5 that segregated with hearing loss in these families. The three novel mutations are all missense variants within exon 8 that are predicted computationally to decrease splicing efficiency or abolish it completely. We confirmed their functional impact in vitro using mini-genes carrying each mutant DFNA5 exon 8. In so doing, we present the first exonic mutations in DFNA5 to cause deafness, expand the mutational spectrum of DFNA5-related hearing loss, and highlight the importance of assessing the effect of coding variants on splicing.
Collapse
|
93
|
Kazeminasab S, Najmabadi H, Kahrizi K. Intellectual Disability and Ataxia: Genetic Collisions. ARCHIVES OF IRANIAN MEDICINE 2018; 21:29-40. [PMID: 29664668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 11/15/2017] [Indexed: 06/08/2023]
Abstract
Intellectual disability (ID) is a common and highly heterogeneous neurodevelopmental disorder. The prevalence of ID is around 1%-3% in the general population. ID is associated with a wide range of additional neurological disabilities and the results of various studies have disclosed the co-morbidity of ID and ataxia. The aim of this review is elucidation of the common molecular and cellular pathways in the etiology of ID and ataxia. Categorization of these genes with various cellular functions indicates several genetic collisions in the co-occurrence of ID and ataxia.
Collapse
|
94
|
Babanejad M, Adeli OA, Nikzat N, Beheshtian M, Azarafra H, Sadeghnia F, Mohseni M, Najmabadi H, Kahrizi K. SLC52A2 mutations cause SCABD2 phenotype: A second report. Int J Pediatr Otorhinolaryngol 2018; 104:195-199. [PMID: 29287867 DOI: 10.1016/j.ijporl.2017.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 11/15/2017] [Accepted: 11/15/2017] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Autosomal recessive cerebellar ataxias (ARCAs) are a large group of neurodegenerative disorders that manifest mainly in children and young adults. Most ARCAs are heterogeneous with respect to age at onset, severity of disease progression, and frequency of extracerebellar and systemic signs. METHODS The phenotype of a consanguineous Iranian family was characterized using clinical testing and pedigree analysis. Whole-exome sequencing was used to identify the disease-causing gene in this family. RESULTS AND CONCLUSION Using whole exome sequencing (WES), a novel missense mutation in SLC52A2 gene is reported in a consanguineous Iranian family with progressive severe hearing loss, optic atrophy and ataxia. This is the second report of the genotype-phenotype correlation between this syndrome named spinocerebellar ataxia with blindness and deafness type 2 (SCABD2) and SLC52A2 gene.
Collapse
|
95
|
Edizadeh M, Vazehan R, Javadi F, Dehdahsi S, Fadaee M, Faraji Zonooz M, Parsimehr E, Ahangari F, Abolhassani A, Kalhor Z, Fattahi Z, Beheshtian M, Kariminejad A, Akbari MR, Najmabadi H, Nafissi S. De novo Mutation in CACNA1S Gene in a 20-Year-Old Man Diagnosed with Metabolic Myopathy. ARCHIVES OF IRANIAN MEDICINE 2017; 20:617-620. [PMID: 29048924 DOI: 0172009/aim.0010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The calcium channel, voltage-dependent, L-type, alpha 1S subunit (CACNA1S) gene encodes a skeletal Ca2+ channel which is involved in calcium-dependent processes such as muscle contraction and neurotransmitter release. Mutations in this gene have been accompanied by hypo- and normokalemic periodic paralysis, thyrotoxic periodic paralysis, and susceptibility to malignant hyperthermia. We report the clinical and genetic findings in a patient diagnosed with metabolic myopathy who had episodic attacks of muscle pain and weakness but with no family background of the disease. Next-generation sequencing (NGS) using a panel targeting metabolic myopathy and myotonia genes identified a de novo heterozygous pathogenic variant c.3724A>G, p.Arg1242Gly, in exon 30 of CACNA1S. As the second report of this variant, this case may broaden the CACNA1S-related disease spectrum to include normokalemic periodic paralysis.
Collapse
|
96
|
Ivanova EL, Mau-Them FT, Riazuddin S, Kahrizi K, Laugel V, Schaefer E, de Saint Martin A, Runge K, Iqbal Z, Spitz MA, Laura M, Drouot N, Gérard B, Deleuze JF, de Brouwer APM, Razzaq A, Dollfus H, Assir MZ, Nitchké P, Hinckelmann MV, Ropers H, Riazuddin S, Najmabadi H, van Bokhoven H, Chelly J. Homozygous Truncating Variants in TBC1D23 Cause Pontocerebellar Hypoplasia and Alter Cortical Development. Am J Hum Genet 2017; 101:428-440. [PMID: 28823707 DOI: 10.1016/j.ajhg.2017.07.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/19/2017] [Indexed: 01/03/2023] Open
Abstract
Pontocerebellar hypoplasia (PCH) is a heterogeneous group of rare recessive disorders with prenatal onset, characterized by hypoplasia of pons and cerebellum. Mutations in a small number of genes have been reported to cause PCH, and the vast majority of PCH cases are explained by mutations in TSEN54, which encodes a subunit of the tRNA splicing endonuclease complex. Here we report three families with homozygous truncating mutations in TBC1D23 who display moderate to severe intellectual disability and microcephaly. MRI data from available affected subjects revealed PCH, small normally proportioned cerebellum, and corpus callosum anomalies. Furthermore, through in utero electroporation, we show that downregulation of TBC1D23 affects cortical neuron positioning. TBC1D23 is a member of the Tre2-Bub2-Cdc16 (TBC) domain-containing RAB-specific GTPase-activating proteins (TBC/RABGAPs). Members of this protein family negatively regulate RAB proteins and modulate the signaling between RABs and other small GTPases, some of which have a crucial role in the trafficking of intracellular vesicles and are involved in neurological disorders. Here, we demonstrate that dense core vesicles and lysosomal trafficking dynamics are affected in fibroblasts harboring TBC1D23 mutation. We propose that mutations in TBC1D23 are responsible for a form of PCH with small, normally proportioned cerebellum and should be screened in individuals with syndromic pontocereballar hypoplasia.
Collapse
|
97
|
Vermeulen C, Geeven G, de Wit E, Verstegen MJ, Jansen RP, van Kranenburg M, de Bruijn E, Pulit SL, Kruisselbrink E, Shahsavari Z, Omrani D, Zeinali F, Najmabadi H, Katsila T, Vrettou C, Patrinos GP, Traeger-Synodinos J, Splinter E, Beekman JM, Kheradmand Kia S, te Meerman GJ, Ploos van Amstel HK, de Laat W. Sensitive Monogenic Noninvasive Prenatal Diagnosis by Targeted Haplotyping. Am J Hum Genet 2017; 101:326-339. [PMID: 28844486 PMCID: PMC5590845 DOI: 10.1016/j.ajhg.2017.07.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/24/2017] [Indexed: 12/11/2022] Open
Abstract
During pregnancy, cell-free DNA (cfDNA) in maternal blood encompasses a small percentage of cell-free fetal DNA (cffDNA), an easily accessible source for determination of fetal disease status in risk families through non-invasive procedures. In case of monogenic heritable disease, background maternal cfDNA prohibits direct observation of the maternally inherited allele. Non-invasive prenatal diagnostics (NIPD) of monogenic diseases therefore relies on parental haplotyping and statistical assessment of inherited alleles from cffDNA, techniques currently unavailable for routine clinical practice. Here, we present monogenic NIPD (MG-NIPD), which requires a blood sample from both parents, for targeted locus amplification (TLA)-based phasing of heterozygous variants selectively at a gene of interest. Capture probes-based targeted sequencing of cfDNA from the pregnant mother and a tailored statistical analysis enables predicting fetal gene inheritance. MG-NIPD was validated for 18 pregnancies, focusing on CFTR, CYP21A2, and HBB. In all cases we could predict the inherited alleles with >98% confidence, even at relatively early stages (8 weeks) of pregnancy. This prediction and the accuracy of parental haplotyping was confirmed by sequencing of fetal material obtained by parallel invasive procedures. MG-NIPD is a robust method that requires standard instrumentation and can be implemented in any clinic to provide families carrying a severe monogenic disease with a prenatal diagnostic test based on a simple blood draw.
Collapse
|
98
|
Alavi A, Esmaeili S, Nilipour Y, Nafissi S, Tonekaboni SH, Zamani G, Ashrafi MR, Kahrizi K, Najmabadi H, Jazayeri F. LGMD2E is the most common type of sarcoglycanopathies in the Iranian population. J Neurogenet 2017; 31:161-169. [DOI: 10.1080/01677063.2017.1346093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
99
|
Alber M, Kalscheuer VM, Marco E, Sherr E, Lesca G, Till M, Gradek G, Wiesener A, Korenke C, Mercier S, Becker F, Yamamoto T, Scherer SW, Marshall CR, Walker S, Dutta UR, Dalal AB, Suckow V, Jamali P, Kahrizi K, Najmabadi H, Minassian BA. ARHGEF9 disease: Phenotype clarification and genotype-phenotype correlation. NEUROLOGY-GENETICS 2017; 3:e148. [PMID: 28589176 PMCID: PMC5446782 DOI: 10.1212/nxg.0000000000000148] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/14/2017] [Indexed: 01/13/2023]
Abstract
OBJECTIVE We aimed to generate a review and description of the phenotypic and genotypic spectra of ARHGEF9 mutations. METHODS Patients with mutations or chromosomal disruptions affecting ARHGEF9 were identified through our clinics and review of the literature. Detailed medical history and examination findings were obtained via a standardized questionnaire, or if this was not possible by reviewing the published phenotypic features. RESULTS A total of 18 patients (including 5 females) were identified. Six had de novo, 5 had maternally inherited mutations, and 7 had chromosomal disruptions. All females had strongly skewed X-inactivation in favor of the abnormal X-chromosome. Symptoms presented in early childhood with delayed motor development alone or in combination with seizures. Intellectual disability was severe in most and moderate in patients with milder mutations. Males with severe intellectual disability had severe, often intractable, epilepsy and exhibited a particular facial dysmorphism. Patients with mutations in exon 9 affecting the protein's PH domain did not develop epilepsy. CONCLUSIONS ARHGEF9 encodes a crucial neuronal synaptic protein; loss of function of which results in severe intellectual disability, epilepsy, and a particular facial dysmorphism. Loss of only the protein's PH domain function is associated with the absence of epilepsy.
Collapse
|
100
|
Musante L, Püttmann L, Kahrizi K, Garshasbi M, Hu H, Stehr H, Lipkowitz B, Otto S, Jensen LR, Tzschach A, Jamali P, Wienker T, Najmabadi H, Ropers HH, Kuss AW. Mutations of the aminoacyl-tRNA-synthetases SARS and WARS2 are implicated in the etiology of autosomal recessive intellectual disability. Hum Mutat 2017; 38:621-636. [PMID: 28236339 DOI: 10.1002/humu.23205] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 01/06/2017] [Accepted: 02/17/2017] [Indexed: 12/16/2022]
Abstract
Intellectual disability (ID) is the hallmark of an extremely heterogeneous group of disorders that comprises a wide variety of syndromic and non-syndromic phenotypes. Here, we report on mutations in two aminoacyl-tRNA synthetases that are associated with ID in two unrelated Iranian families. In the first family, we identified a homozygous missense mutation (c.514G>A, p.Asp172Asn) in the cytoplasmic seryl-tRNA synthetase (SARS) gene. The mutation affects the enzymatic core domain of the protein and impairs its enzymatic activity, probably leading to reduced cytoplasmic tRNASer concentrations. The mutant protein was predicted to be unstable, which could be substantiated by investigating ectopic mutant SARS in transfected HEK293T cells. In the second family, we found a compound heterozygous genotype of the mitochondrial tryptophanyl-tRNA synthetase (WARS2) gene, comprising a nonsense mutation (c.325delA, p.Ser109Alafs*15), which very likely entails nonsense-mediated mRNA decay and a missense mutation (c.37T>G, p.Trp13Gly). The latter affects the mitochondrial localization signal of WARS2, causing protein mislocalization. Including AIMP1, which we have recently implicated in the etiology of ID, three genes with a role in tRNA-aminoacylation are now associated with this condition. We therefore suggest that the functional integrity of tRNAs in general is an important factor in the development and maintenance of human cognitive functions.
Collapse
|