Browsing by Subject "DELETIONS"

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  • Pausch, Hubert; Venhoranta, Heli; Wurmser, Christine; Hakala, Kalle; Iso-Touru, Terhi; Sironen, Anu; Vingborg, Rikke K.; Lohi, Hannes; Soderquist, Lennart; Fries, Ruedi; Andersson, Magnus (2016)
    Background: Artificial insemination is widely used in many cattle breeding programs. Semen samples of breeding bulls are collected and closely examined immediately after collection at artificial insemination centers. Only ejaculates without anomalous findings are retained for artificial insemination. Although morphological aberrations of the spermatozoa are a frequent reason for discarding ejaculates, the genetic determinants underlying poor semen quality are scarcely understood. Results: A tail stump sperm defect was observed in three bulls of the Swedish Red cattle breed. The spermatozoa of affected bulls were immotile because of severely disorganized tails indicating disturbed spermatogenesis. We genotyped three affected bulls and 18 unaffected male half-sibs at 46,035 SNPs and performed homozygosity mapping to map the fertility disorder to an 8.42 Mb interval on bovine chromosome 13. The analysis of whole-genome re-sequencing data of an affected bull and 300 unaffected animals from eleven cattle breeds other than Swedish Red revealed a 1 bp deletion (Chr13: 24,301,425 bp, ss1815612719) in the eleventh exon of the armadillo repeat containing 3-encoding gene (ARMC3) that was compatible with the supposed recessive mode of inheritance. The deletion is expected to alter the reading frame and to induce premature translation termination (p.A451fs26). The mutated protein is shortened by 401 amino acids (46 %) and lacks domains that are likely essential for normal protein function. Conclusions: We report the phenotypic and genetic characterization of a sterilizing tail stump sperm defect in the Swedish Red cattle breed. Exploiting high-density genotypes and massive re-sequencing data enabled us to identify the most likely causal mutation for the fertility disorder in bovine ARMC3. Our results provide the basis for monitoring the mutated variant in the Swedish Red cattle population and for the early identification of infertile animals.
  • Sironen, Anu; Uimari, Pekka; Venhoranta, Heli; Andersson, Magnus; Vilkki, Johanna (2011)
    ABSTRACT: BACKGROUND: Male infertility is an increasing problem in all domestic species including man. Localization and identification of genes involved in defects causing male infertility provide valuable information of specific events in sperm development. Sperm development is a complex process, where diploid spermatogonia develop into haploid, highly specialized spermatozoa. Correct expression and function of various genes and their protein products are required for production of fertile sperm. We have identified an infertility defect in Finnish Yorkshire boars caused by spermatogenic arrest. The aim of this study was to locate the disease associated region using genome wide screen with the PorcineSNP60 Beadchip and identify the causal mutation by candidate gene approach. RESULTS: In the Finnish Yorkshire pig population the spermatogenic arrest (SA) defect appears to be of genetic origin and causes severe degeneration of germ cells and total absence of spermatozoa. Genome wide scan with the PorcineSNP60 Beadchip localized the SA defect to porcine chromosome 12 in a 2 Mbp region. Sequencing of a candidate gene Tex14 revealed a 51 bp insertion within exon 27, which caused differential splicing of the exon and created a premature translation stop codon. The expression of Tex14 was markedly down regulated in the testis of a SA affected boar compared to control boars and no protein product was identified by Western blotting. The SA insertion sequence was also found within intron 27 in all analyzed animals, thus the insertion appears to be a possible duplication event. CONCLUSION: In this study we report the identification of a causal mutation for infertility caused by spermatogenic arrest at an early meiotic phase. Our results highlight the role of TEX14 specifically in spermatogenesis and the importance of specific genomic remodeling events as causes for inherited defects.
  • Haider, Zahra; Larsson, Pär; Landfors, Mattias; Köhn, Linda; Schmiegelow, Kjeld; Flægstad, Trond; Kanerva, Jukka; Heyman, Mats; Hultdin, Magnus; Degerman, Sofie (2019)
    Classification of pediatric T-cell acute lymphoblastic leukemia (T-ALL) patients into CIMP (CpG Island Methylator Phenotype) subgroups has the potential to improve current risk stratification. To investigate the biology behind these CIMP subgroups, diagnostic samples from Nordic pediatric T-ALL patients were characterized by genome-wide methylation arrays, followed by targeted exome sequencing, telomere length measurement, and RNA sequencing. The CIMP subgroups did not correlate significantly with variations in epigenetic regulators. However, the CIMP+ subgroup, associated with better prognosis, showed indicators of longer replicative history, including shorter telomere length (P = 0.015) and older epigenetic (P <0.001) and mitotic age (P <0.001). Moreover, the CIMP+ subgroup had significantly higher expression of ANTP homeobox oncogenes, namely TLX3, HOXA9, HOXA10, and NKX2-1, and novel genes in T-ALL biology including PLCB4, PLXND1, and MYO18B. The CIMP- subgroup, with worse prognosis, was associated with higher expression of TAL1 along with frequent STIL-TAL1 fusions (2/40 in CIMP+ vs 11/24 in CIMP-), as well as stronger expression of BEX1. Altogether, our findings suggest different routes for leukemogenic transformation in the T-ALL CIMP subgroups, indicated by different replicative histories and distinct methylomic and transcriptomic profiles. These novel findings can lead to new therapeutic strategies.
  • Lundin, Catarina; Forestier, Erik; Andersen, Mette Klarskov; Autio, Kirsi; Barbany, Gisela; Cavelier, Lucia; Golovleva, Irina; Heim, Sverre; Heinonen, Kristiina; Hovland, Randi; Johannsson, Johann H.; Kjeldsen, Eigil; Nordgren, Ann; Palmqvist, Lars; Johansson, Bertil; Nordic Soc Pediat Hematology Oncol; Swedish Cytogenetic Leukemia Study; NOPHO Leukemia Cytogenetic Study G (2014)
  • Pettersson, Maria; Viljakainen, Heli; Loid, Petra; Mustila, Taina; Pekkinen, Minna; Armenio, Miriam; Andersson-Assarsson, Johanna C.; Makitie, Outi; Lindstrand, Anna (2017)
    Context: Only a few genetic causes for childhood obesity have been identified to date. Copy number variants (CNVs) are known to contribute to obesity, both syndromic (15q11.2 deletions, Prader-Willi syndrome) and nonsyndromic (16p11.2 deletions) obesity. Objective: To study the contribution of CNVs to early-onset obesity and evaluate the expression of candidate genes in subcutaneous adipose tissue. Design and Setting: A case-control study in a tertiary academic center. Participants: CNV analysis was performed on 90 subjects with early-onset obesity and 67 normalweight controls. Subcutaneous adipose tissue from body mass index-discordant siblings was used for the gene expression analyses. Main Outcome Measures: We used custom high-density array comparative genomic hybridization with exon resolution in 1989 genes, including all known obesity loci. The expression of candidate genes was assessed using microarray analysis of messenger RNA from subcutaneous adipose tissue. Results: We identified rare CNVs in 17 subjects (19%) with obesity and 2 controls (3%). In three cases (3%), the identified variant involved a known syndromic lesion (22q11.21 duplication, 1q21.1 deletion, and 16p11.2 deletion, respectively), although the others were not known. Seven CNVs in 10 families were inherited and segregated with obesity. Expression analysis of 37 candidate genes showed discordant expression for 10 genes (PCM1, EFEMP1, MAMLD1, ACP6, BAZ2B, SORBS1, KLF15, MACROD2, ATR, and MBD5). Conclusions: Rare CNVs contribute possibly pathogenic alleles to a substantial fraction of children with early-onset obesity. The involved genes might provide insights into pathogenic mechanisms and involved cellular pathways. These findings highlight the importance of CNV screening in children with early-onset obesity.
  • Blatter, Robert; Tschupp, Benjamin; Aretz, Stefan; Bernstein, Inge; Colas, Chrystelle; Evans, D. Gareth; Genuardi, Maurizio; Hes, Frederik J.; Hueneburg, Robert; Jarvinen, Heikki; Lalloo, Fiona; Moeslein, Gabriela; Renkonen-Sinisalo, Laura; Resta, Nicoletta; Spier, Isabel; Varvara, Dora; Vasen, Hans; Latchford, Andrew R.; Heinimann, Karl (2020)
    Purpose Juvenile polyposis syndrome (JPS) is a rare, autosomal-dominantly inherited cancer predisposition caused in approximately 50% of cases by pathogenic germline variants in SMAD4 and BMPR1A. We aimed to gather detailed clinical and molecular genetic information on JPS disease expression to provide a basis for management guidelines and establish open access variant databases. Methods We performed a retrospective, questionnaire-based European multicenter survey on and established a cohort of SMAD4/BMPR1A pathogenic variant carriers from the medical literature. Results We analyzed questionnaire-based data on 221 JPS patients (126 kindreds) from ten European centers and retrieved literature-based information on 473 patients. Compared with BMPR1A carriers, SMAD4 carriers displayed anemia twice as often (58% vs. 26%), and exclusively showed overlap symptoms with hemorrhagic telangiectasia (32%) and an increased prevalence (39% vs. 13%) of gastric juvenile polyps. Cancer, reported in 15% of JPS patients (median age 41 years), mainly occurred in the colorectum (overall: 62%, SMAD4: 58%, BMPR1A: 88%) and the stomach (overall: 21%; SMAD4: 27%, BMPR1A: 0%). Conclusion This comprehensive retrospective study on genotype-phenotype correlations in 694 JPS patients corroborates previous observations on JPS in general and SMAD4 carriers in particular, facilitates recommendations for clinical management, and provides the basis for open access variant SMAD4 and BMPR1A databases.
  • Joensuu, Heikki; Wardelmann, Eva; Sihto, Harri; Eriksson, Mikael; Hall, Kirsten Sundby; Reichardt, Annette; Hartmann, Joerg T.; Pink, Daniel; Cameron, Silke; Hohenberger, Peter; Al-Batran, Salah-Eddin; Schlemmer, Marcus; Bauer, Sebastian; Nilsson, Bengt; Kallio, Raija; Junnila, Jouni; Vehtari, Aki; Reichardt, Peter (2017)
    IMPORTANCE Little is known about whether the duration of adjuvant imatinib influences the prognostic significance of KIT proto-oncogene receptor tyrosine kinase (KIT) and platelet-derived growth factor receptor a (PDGFRA) mutations. OBJECTIVE To investigate the effect of KIT and PDGFRA mutations on recurrence-free survival (RFS) in patients with gastrointestinal stromal tumors (GISTs) treated with surgery and adjuvant imatinib. DESIGN, SETTING, AND PARTICIPANTS This exploratory study is based on the Scandinavian Sarcoma Group VIII/Arbeitsgemeinschaft Internistische Onkologie (SSGXVIII/AIO) multicenter clinical trial. Between February 4, 2004, and September 29, 2008, 400 patients who had undergone surgery for GISTs with a high risk of recurrence were randomized to receive adjuvant imatinib for 1 or 3 years. Of the 397 patients who provided consent, 341 (85.9%) had centrally confirmed, localized GISTs with mutation analysis for KIT and PDGFRA performed centrally using conventional sequencing. During a median follow-up of 88 months (completed December 31, 2013), 142 patients had GIST recurrence. Data of the evaluable population were analyzed February 4, 2004, through December 31, 2013. MAIN OUTCOMES AND MEASURES The main outcome was RFS. Mutations were grouped by the gene and exon. KIT exon 11 mutations were further grouped as deletion or insertion-deletion mutations, substitution mutations, insertion or duplication mutations, and mutations that involved codons 557 and/or 558. RESULTS Of the 341 patients (175 men and 166women; median age at study entry, 62 years) in the 1-year group and 60 years in the 3-year group), 274 (80.4%) had GISTs with a KIT mutation, 43 (12.6%) had GISTs that harbored a PDGFRA mutation, and 24 (7.0%) had GISTs thatwere wild type for these genes. PDGFRA mutations and KIT exon 11 insertion or duplication mutations were associated with favorable RFS, whereas KIT exon 9 mutations were associated with unfavorable outcome. Patients with KIT exon 11 deletion or insertion-deletion mutation had better RFS when allocated to the 3-year group compared with the 1-year group (5-year RFS, 71.0% vs 41.3%; P CONCLUSIONS AND RELEVANCE Patients with KIT exon 11 deletion mutations benefit most from the longer duration of adjuvant imatinib. The duration of adjuvant imatinib modifies the risk of GIST recurrence associated with some KIT mutations, including deletions that affect exon 11 codons 557 and/or 558.
  • Lal, Dennis; Steinbruecker, Sandra; Schubert, Julian; Sander, Thomas; Becker, Felicitas; Weber, Yvonne; Lerche, Holger; Thiele, Holger; Krause, Roland; Lehesjoki, Anna-Elina; Nuernberg, Peter; Palotie, Aarno; Neubauer, Bernd A.; Muhle, Hiltrud; Stephani, Ulrich; Helbig, Ingo; Becker, Albert J.; Schoch, Susanne; Hansen, Joerg; Dorn, Thomas; Hohl, Christin; Luescher, Nicole; von Spiczak, Sarah; Lemke, Johannes R.; Epicure Consortium; EuroEPINOMICS-CoGIE Consortium (2015)
    Recently, mutations and deletions in the GRIN2A gene have been identified to predispose to benign and severe idiopathic focal epilepsies (IFE), revealing a higher incidence of GRIN2A alterations among the more severe phenotypes. This study aimed to explore the phenotypic boundaries of GRIN2A mutations by investigating patients with the two most common epilepsy syndromes: (i) idiopathic generalized epilepsy (IGE) and (ii) temporal lobe epilepsy (TLE). Whole exome sequencing data of 238 patients with IGE as well as Sanger sequencing of 84 patients with TLE were evaluated for GRIN2A sequence alterations. Two additional independent cohorts comprising 1469 IGE and 330 TLE patients were screened for structural deletions (>40 kb) involving GRIN2A. Apart from a presumably benign, non-segregating variant in a patient with juvenile absence epilepsy, neither mutations nor deletions were detected in either cohort. These findings suggest that mutations in GRIN2A preferentially are involved in genetic variance of pediatric IFE and do not contribute significantly to either adult focal epilepsies as TLE or generalized epilepsies. (C) 2015 Elsevier B.V. All rights reserved.
  • Leu, Costin; Bautista, Jocelyn F.; Sudarsanam, Monica; Niestroj, Lisa-Marie; Stefanski, Arthur; Ferguson, Lisa; Daly, Mark J.; Jehi, Lara; Najm, Imad M.; Busch, Robyn M.; Lal, Dennis (2020)
    Psychogenic nonepileptic seizures (PNES) are diagnosed in approximately 30% of patients referred to tertiary care epilepsy centers. Little is known about the molecular pathology of PNES, much less about possible underlying genetic factors. We generated whole-exome sequencing and whole-genome genotyping data to identify rare, pathogenic (P) or likely pathogenic (LP) variants in 102 individuals with PNES and 448 individuals with focal (FE) or generalized (GE) epilepsy. Variants were classified for all individuals based on the ACMG-AMP 2015 guidelines. For research purposes only, we considered genes associated with neurological or psychiatric disorders as candidate genes for PNES. We observe in this first genetic investigation of PNES that six (5.88%) individuals with PNES without coexistent epilepsy carry P/LP variants (deletions at 10q11.22-q11.23, 10q23.1-q23.2, distal 16p11.2, and 17p13.3, and nonsynonymous variants in NSD1 and GABRA5). Notably, the burden of P/LP variants among the individuals with PNES was similar and not significantly different to the burden observed in the individuals with FE (3.05%) or GE (1.82%) (PNES vs. FE vs. GE (3x2 chi (2)), P=0.30; PNES vs. epilepsy (2x2 chi (2)), P=0.14). The presence of variants in genes associated with monogenic forms of neurological and psychiatric disorders in individuals with PNES shows that genetic factors are likely to play a role in PNES or its comorbidities in a subset of individuals. Future large-scale genetic research studies are needed to further corroborate these interesting findings in PNES.
  • Messina, Andrea; Pulli, Kristiina; Santini, Sara; Acierno, James; Kansakoski, Johanna; Cassatella, Daniele; Xu, Cheng; Casoni, Filippo; Malone, Samuel A.; Ternier, Gaetan; Conte, Daniele; Sidis, Yisrael; Tommiska, Johanna; Vaaralahti, Kirsi; Dwyer, Andrew; Gothilf, Yoav; Merlo, Giorgio R.; Santoni, Federico; Niederlander, Nicolas J.; Giacobini, Paolo; Raivio, Taneli; Pitteloud, Nelly (2020)
    Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disorder characterized by infertility and the absence of puberty. Defects in GnRH neuron migration or altered GnRH secretion and/or action lead to a severe gonadotropin-releasing hormone (GnRH) deficiency. Given the close developmental association of GnRH neurons with the olfactory primary axons, CHH is often associated with anosmia or hyposmia, in which case it is defined as Kallmann syndrome (KS). The genetics of CHH are heterogeneous, and >40 genes are involved either alone or in combination. Several CHH-related genes controlling GnRH ontogeny encode proteins containing fibronectin-3 (FN3) domains, which are important for brain and neural development. Therefore, we hypothesized that defects in other FN3-superfamily genes would underlie CHH. Next-generation sequencing was performed for 240 CHH unrelated probands and filtered for rare, protein-truncating variants (PTVs) in FN3-superfamily genes. Compared to gnomAD controls the CHH cohort was statistically enriched for PTVs in neuron-derived neurotrophic factor (NDNF) (p = 1.40 x 10(-6)). Three heterozygous PTVs (p.Lys62*, p.Tyr128Thrfs*55, and p.Trp469*, all absent from the gnomAD database) and an additional heterozygous missense mutation (p.Thr201Ser) were found in four KS probands. Notably, NDNF is expressed along the GnRH neuron migratory route in both mouse embryos and human fetuses and enhances GnRH neuron migration. Further, knock down of the zebrafish ortholog of NDNF resulted in altered GnRH migration. Finally, mice lacking Ndnf showed delayed GnRH neuron migration and altered olfactory axonal projections to the olfactory bulb; both results are consistent with a role of NDNF in GnRH neuron development. Altogether, our results highlight NDNF as a gene involved in the GnRH neuron migration implicated in KS.
  • Liu, Fulu; Zhang, Yating; Qiao, Wanjin; Zhu, Duolong; Xu, Haijin; Saris, Per Erik Joakim; Qiao, Mingqiang (2019)
    Background After 2.83% genome reduction in Lactococcus lactis NZ9000, a good candidate host for proteins production was obtained in our previous work. However, the gene deletion process was time consuming and laborious. Here, we proposed a convenient gene deletion method suitable for large-scale genome reduction in L. lactis NZ9000. Results Plasmid pNZ5417 containing a visually selectable marker P-nisZ-lacZ was constructed, which allowed more efficient and convenient screening of gene deletion mutants. Using this plasmid, two large nonessential DNA regions, L-4A and L-5A, accounting for 1.25% of the chromosome were deleted stepwise in L. lactis 9k-3. When compared with the parent strain, the mutant L. lactis 9k-5A showed better growth characteristics, transformability, carbon metabolic capacity, and amino acids biosynthesis. Conclusions Thus, this study provides a convenient and efficient system for large-scale genome deletion in L. lactis through application of visually selectable marker, which could be helpful for rapid genome streamlining and generation of restructured L. lactis strains that can be used as cell factories.
  • Garone, Caterina; Taylor, Robert W.; Nascimento, Andres; Poulton, Joanna; Fratter, Carl; Dominguez-Gonzalez, Cristina; Evans, Julie C.; Loos, Mariana; Isohanni, Pirjo; Suomalainen, Anu; Ram, Dipak; Hughes, M. Imelda; McFarland, Robert; Barca, Emanuele; Gomez, Carlos Lopez; Jayawant, Sandeep; Thomas, Neil D.; Manzur, Adnan Y.; Kleinsteuber, Karin; Martin, Miguel A.; Kerr, Timothy; Gorman, Grainne S.; Sommerville, Ewen W.; Chinnery, Patrick F.; Hofer, Monika; Karch, Christoph; Ralph, Jeffrey; Camara, Yolanda; Madruga-Garrido, Marcos; Dominguez-Carral, Jana; Ortez, Carlos; Emperador, Sonia; Montoya, Julio; Chakrapani, Anupam; Kriger, Joshua F.; Schoenaker, Robert; Levin, Bruce; Thompson, John L. P.; Long, Yuelin; Rahman, Shamima; Donati, Maria Alice; DiMauro, Salvatore; Hirano, Michio (2018)
    Background Thymine kinase 2 (TK2) is a mitochondrial matrix protein encoded in nuclear DNA and phosphorylates the pyrimidine nucleosides: thymidine and deoxycytidine. Autosomal recessive TK2 mutations cause a spectrum of disease from infantile onset to adult onset manifesting primarily as myopathy. Objective To perform a retrospective natural history study of a large cohort of patients with TK2 deficiency. Methods The study was conducted by 42 investigators across 31 academic medical centres. Results We identified 92 patients with genetically confirmed diagnoses of TK2 deficiency: 67 from literature review and 25 unreported cases. Based on clinical and molecular genetics findings, we recognised three phenotypes with divergent survival: (1) infantile-onset myopathy (42.4%) with severe mitochondrial DNA (mtDNA) depletion, frequent neurological involvement and rapid progression to early mortality (median post-onset survival (POS) 1.00, CI 0.58 to 2.33 years); (2) childhood-onset myopathy (40.2%) with mtDNA depletion, moderate-to-severe progression of generalised weakness and median POS at least 13 years; and (3) late-onset myopathy (17.4%) with mild limb weakness at onset and slow progression to respiratory insufficiency with median POS of 23 years. Ophthalmoparesis and facial weakness are frequent in adults. Muscle biopsies show multiple mtDNA deletions often with mtDNA depletion. Conclusions In TK2 deficiency, age at onset, rate of weakness progression and POS are important variables that define three clinical subtypes. Nervous system involvement often complicates the clinical course of the infantile-onset form while extraocular muscle and facial involvement are characteristic of the late-onset form. Our observations provide essential information for planning future clinical trials in this disorder.
  • Ciesielski, Grzegorz L.; Nadalutti, Cristina A.; Oliveira, Marcos T.; Jacobs, Howard T.; Griffith, Jack D.; Kaguni, Laurie S. (2018)
    Pathological conditions impairing functions of mitochondria often lead to compensatory upregulation of the mitochondrial DNA (mtDNA) replisome machinery, and the replicative DNA helicase appears to be a key factor in regulating mtDNA copy number. Moreover, mtDNA helicase mutations have been associated with structural rearrangements of themitochondrial genome. To evaluate the effects of elevated levels of the mtDNA helicase on the integrity and replication of the mitochondrial genome, we overexpressed the helicase in Drosophila melanogaster Schneider cells and analyzed the mtDNA by two-dimensional neutral agarose gel electrophoresis and electron microscopy. We found that elevation of mtDNA helicase levels increases the quantity of replication intermediates and alleviates pausing at the replication slow zones. Though we did not observe a concomitant alteration in mtDNA copy number, we observed deletions specific to the segment of repeated elements in the immediate vicinity of the origin of replication, and an accumulation of species characteristic of replication fork stalling. We also found elevated levels of RNA that are retained in the replication intermediates. Together, our results suggest that upregulation of mtDNA helicase promotes the process of mtDNA replication but also results in genome destabilization.
  • Tanaka, Atsushi; Ide, Tomomi; Fujino, Takeo; Onitsuka, Ken; Ikeda, Masataka; Takehara, Takako; Hata, Yuko; Ylikallio, Emil; Tyynismaa, Henna; Suomalainen, Anu; Sunagawa, Kenji (2013)
  • Torella, Annalaura; Zanobio, Mariateresa; Zeuli, Roberta; Blanco, Francesca del Vecchio; Savarese, Marco; Giugliano, Teresa; Garofalo, Arcomaria; Piluso, Giulio; Politano, Luisa; Nigro, Vincenzo (2020)
    A nonsense mutation adds a premature stop signal that hinders any further translation of a protein-coding gene, usually resulting in a null allele. To investigate the possible exceptions, we used theDMDgene as an ideal model. First, because dystrophin absence causes Duchenne muscular dystrophy (DMD), while its reduction causes Becker muscular dystrophy (BMD). Second, theDMDgene is X-linked and there is no second allele that can interfere in males. Third, databases are accumulating reports on many mutations and phenotypic data. Finally, becauseDMDmutations may have important therapeutic implications. For our study, we analyzed large databases (LOVD, HGMD and ClinVar) and literature and revised critically all data, together with data from our internal patients. We totally collected 2593 patients. Positioning these mutations along the dystrophin transcript, we observed a nonrandom distribution of BMD-associated mutations within selected exons and concluded that the position can be predictive of the phenotype. Nonsense mutations always cause DMD when occurring at any point in fifty-one exons. In the remaining exons, we found milder BMD cases due to early 5' nonsense mutations, if reinitiation can occur, or due to late 3' nonsense when the shortened product retains functionality. In the central part of the gene, all mutations in some in-frame exons, such as in exons 25, 31, 37 and 38 cause BMD, while mutations in exons 30, 32, 34 and 36 cause DMD. This may have important implication in predicting the natural history and the efficacy of therapeutic use of drug-stimulated translational readthrough of premature termination codons, also considering the action of internal natural rescuers. More in general, our survey confirm that a nonsense mutation should be not necessarily classified as a null allele and this should be considered in genetic counselling.