Limb Girdle Muscular Dystrophy Type 2E Due to a Novel Large Deletion in SGCB Gene

How to Cite This Article: Ghafouri-Fard S, Hashemi-Gorji F, Fardaei M, Miryounesi M. Limb Girdle Muscular Dystrophy Type 2E Due to a Novel Large Deletion in SGCB Gene. Iran J Child Neurol. Summer 2017; 11(3):57-60.  AbstractAutosomal recessive limb-girdle muscular dystrophies (LGMD type 2) are a group of clinically and genetically heterogeneous diseases with the main characteristics of weakness and wasting of the pelvic and shoulder girdle muscles. Among them are sarcoglycanopathies caused by mutations in at least four genes named SGCA, SGCB, SGCG and SGCD. Here we report a consanguineous Iranian family with two children affected with LGMD type 2E.Mutation analysis revealed a novel homozygous exon 2 deletion of SGCB gene in the patients with the parents being heterozygous for this deletion. This result presents a novel underlying genetic mechanism for LGMD type 2E.References1. Lo HP, Cooper ST, Evesson FJ, Seto JT, Chiotis M, Tay V et al. Limb-girdle muscular dystrophy: diagnostic evaluation, frequency and clues to pathogenesis. Neuromuscul Disord 2008;18(1):34-44.2. Bushby KM, Beckmann JS. The 105th ENMC sponsored workshop: pathogenesis in the non-sarcoglycan limbgirdle muscular dystrophies, Naarden, April 12-14, 2002. Neuromuscul Disord 2003;13(1):80-90.3. Zatz M, de Paula F, Starling A, Vainzof M. The 10 autosomal recessive limb-girdle muscular dystrophies. Neuromuscul Disord 2003;13(7-8):532-44.4. Araishi K, Sasaoka T, Imamura M, Noguchi S, Hama H, Wakabayashi E et al. Loss of the sarcoglycan complex and sarcospan leads to muscular dystrophy in beta-sarcoglycan-deficient mice. Hum Mol Genet 1999;8(9):1589-98.5. Pegoraro E, Hoffman EP. Limb-girdle muscular dystrophy overview. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. 2012.6. Straub V, Bushby K. The childhood limb-girdle muscular dystrophies. Semin Pediatr Neurol 2006;13(2):104-14.7. Kaindl AM, Jakubiczka S, Lucke T, Bartsch O, Weis J, Stoltenburg-Didinger G, et al. Homozygous microdeletion of chromosome 4q11-q12 causes severe limb-girdle muscular dystrophy type 2E with joint hyperlaxity and contractures. Hum Mut 2005;26(3):279- 80.8. Trabelsi M, Kavian N, Daoud F, Commere V, Deburgrave N, Beugnet C et al. Revised spectrum of mutations in sarcoglycanopathies. European journal of human genetics. Europ J Hum Gene 2008;16(7):793- 803.9. Rivas E, Teijeira S, dos Santos MR, Porrit I, Leturcq F, Fernandez JM et al. Beta-sarcoglycanopathy (LGMD 2E) in a Spanish family. Acta Myol 2004;23(3):159-62.10. Barresi R, Di Blasi C, Negri T, Brugnoni R, Vitali A, Felisari G et al. Disruption of heart sarcoglycan complex and severe cardiomyopathy caused by beta sarcoglycan mutations. J Med Gene 2000;37(2):102-7

Association of a Novel Nonsense Mutation in KIAA1279 with Goldberg-Shprintzen Syndrome

How to Cite This Article: Salehpour Sh, Hashemi-Gorji F, Soltani Z, Ghafouri-Fard S, Miryounesi M. Association of a Novel Nonsense Mutation in KIAA1279 with Goldberg-Shprintzen Syndrome. Iran J Child Neurol. Winter 2017; 11(1):70-74.AbstractGoldberg-Shprintzen syndrome (OMIM 609460) (GOSHS) is an autosomal recessive multiple congenital anomaly syndrome distinguished by intellectual disability, microcephaly, and dysmorphic facial characteristics. Most affected individuals also have Hirschsprung disease and/or gyral abnormalities of the brain. This syndrome has been associated with KIAA1279 gene mutations at 10q22.1. Here we report a 16 yr old male patient referred to Center for Comprehensive Genetic Services, Tehran, Iran in 2015 with cardinal features of GOSHS in addition to refractory seizures. Whole exome sequencing in the patient revealed a novel nonsense (stop gain) homozygous mutation in KIAA1279 gene (KIAA1279: NM_015634:exon6:c.C976T:p.Q326X).Considering the wide range of phenotypic variations in GOSHS, relying on phenotypic characteristics for discrimination of GOSH from similar syndromes may lead to misdiagnosis. Consequently, molecular diagnostic tools would help in accurate diagnosis of such overlapping phenotypes.References1. Goldberg R, Shprintzen R. Hirschsprung megacolon and cleft palate in two sibs. J Craniofac Genet Dev Biol 1980;1(2):185-9. 2. Yomo A, Taira T, Kondo I. Goldberg-Shprintzen syndrome: Hirschsprung disease, hypotonia, and ptosis in sibs. Am J Med Genet 1991;41(2):188-91.3. Drevillon L, Megarbane A, Demeer B, Matar C, Benit P, Briand-Suleau A, et al. KBP-cytoskeleton interactions underlie developmental anomalies in Goldberg-Shprintzen syndrome. Hum Mol Genet 2013;22(12):2387-99.4. Brooks AS, Bertoli-Avella AM, Burzynski GM, Breedveld GJ, Osinga J, Boven LG, et al. Homozygous nonsense mutations in KIAA1279 are associated with malformations of the central and enteric nervous systems. Am J Med Genet 2005;77(1):120-6.5. Blatch GL, Lassle M. The tetratricopeptide repeat: a structural motif mediating protein-protein interactions. BioEssays 1999;21(11):932-9.6. Alves MM, Burzynski G, Delalande J-M, Osinga J, van der Goot A, Dolga AM, et al. KBP interacts with SCG10, linking Goldberg–Shprintzen syndrome to microtubule dynamics and neuronal differentiation. Hum Mol Genet 2010:ddq280.7. Valence S, Poirier K, Lebrun N, Saillour Y, Sonigo P, Bessières B, et al. Homozygous truncating mutation of the KBP gene, encoding a KIF1B-binding protein, in a familial case of fetal polymicrogyria. Neurogenetics2013;14(3-4):215-24.8. Murphy HR, Carver MJ, Brooks AS, Kenny SE, Ellis IH. Two brothers with Goldberg-Shprintzen syndrome. Clinl Dysmorphol 2006;15(3):165-9

Analysis of Cytogenetic Abnormalities in Iranian Patients with Syndromic Autism Spectrum Disorder: A Case Series

Objective Autism spectrum disorder is a heterogeneous neuropsychiatric group of pervasive development disorder, which is mostly diagnosed through the intricate behavioral phenotype. According to strong genetic involvement, detecting the chromosome regions and the key genes linked to autism can help to elucidate its etiology. The present study aims to investigate the value of cytogenetic analysis in syndromic autism as well as to find an association between autism and chromosome abnormalities. Materials & Methods Thirty-six autism patients from 30 families, diagnosed clinically with DSM-5 criteria, were recruited. The syndromic patients who had additional clinical features involving development delay, attention deficit, hyperactivity disorder, seizure, language, and intellectual impairment were selected due to elevating the detection rate. Cytogenetics analysis was performed using GTG banding on the patients' cultured fibroblasts. Moreover, array-comparative genomic hybridization was also performed for a patient with a de novo and novel variant.   Results Karyotype analysis in 36 syndromic autism patients detected chromosomal abnormalities in two (5.6%) families, including 46,XY,dup(15)(q11.1q11.2) and 46,XX,ins(7)(q11.1q21.3)dn. In the latter, array-comparative genomic hybridization detected three abnormalities on chromosome 7, including deletion and insertion on both arms; 46,XX,del(7)(q21.11q21.3),dup(7)(p11.2p14.1p12.3)dn. Conclusion We reported a novel and de novo cytogenetic abnormality on chromosome 7 in an Iranian patient diagnosed with syndromic autism. However, the detection rate in syndromic autism was low which implies that it cannot be utilized as the only diagnostic procedure

Human germline heterozygous gain-of-function STAT6 variants cause severe allergic disease

STAT6 (signal transducer and activator of transcription 6) is a transcription factor that plays a central role in the pathophysiology of allergic inflammation. We have identified 16 patients from 10 families spanning three continents with a profound phenotype of early-life onset allergic immune dysregulation, widespread treatment-resistant atopic dermatitis, hypereosinophilia with esosinophilic gastrointestinal disease, asthma, elevated serum IgE, IgE-mediated food allergies, and anaphylaxis. The cases were either sporadic (seven kindreds) or followed an autosomal dominant inheritance pattern (three kindreds). All patients carried monoallelic rare variants in STAT6 and functional studies established their gain-of-function (GOF) phenotype with sustained STAT6 phosphorylation, increased STAT6 target gene expression, and TH2 skewing. Precision treatment with the anti-IL-4Rα antibody, dupilumab, was highly effective improving both clinical manifestations and immunological biomarkers. This study identifies heterozygous GOF variants in STAT6 as a novel autosomal dominant allergic disorder. We anticipate that our discovery of multiple kindreds with germline STAT6 GOF variants will facilitate the recognition of more affected individuals and the full definition of this new primary atopic disorder

A Novel Missense Mutation in CLCN1 Gene in a Family with Autosomal Recessive Congenital Myotonia

Congenital recessive myotonia is a rare genetic disorder caused by mutations in CLCN1, which codes for the main skeletal muscle chloride channel ClC-1. More than 120 mutations have been found in this gene. The main feature of this disorder is muscle membrane hyperexcitability. Here, we report a 59-year male patient suffering from congenital myotonia. He had transient generalized myotonia, which started in early childhood. We analyzed CLCN1 sequence in this patient and other members of his family. We found a new missense mutation in CLCN1 gene (c.1886T>C, p.Leu629Pro). Co-segregation of this mutation with the disease was demonstrated by direct sequencing of the fragment in affected as well as unaffected members of this family. In addition, in silico analyses predicted that this nucleotide change would impair the protein function. Thus, this new nucleotide variation can be used for prenatal diagnosis in this family

Functional Analysis of A Novel Splicing Mutation in The Mutase Gene of Two Unrelated Pedigrees

Objective: Methylmalonic acidura (MMA) is a rare autosomal recessive inborn error of metabolism. In this study we present a novel nucleotide change in the mutase (MUT) gene of two unrelated Iranian pedigrees and introduce the methods used for its functional analysis. Materials and Methods: Two probands with definite diagnosis of MMA and a common novel variant in the MUT were included in a descriptive study. Bioinformatic prediction of the splicing variant was done with different prediction servers. Reverse transcription- polymerase chain reaction (RT-PCR) was done for splicing analysis and the products were analyzed by sequencing. Results: The included index patients showed elevated levels of propionylcarnitine (C3). Urine organic acid analysis confirmed the diagnosis of MMA, and screening for mutations in the MUT revealed a novel C to G variation at the 3´ splice acceptor site in intron 12. In silico analysis suggested the change as a mutation in a conserved sequence. The splicing analysis showed that the C to G nucleotide change at position -3 in the acceptor splice site can lead to retention of the intron 12 sequence. Conclusion: This is the first report of a mutation at the position -3 in the MUT intron 12 (c.2125-3C>G). The results suggest that the identified variation can be associated with the typical clinical manifestations of MMA

Mental retardation due to chromosomal translocation in an Iranian consanguineous family: report of three cases

Background: Mental retardation is defined as impaired mental capacity and ability to comply with environmental and social conditions. Chromosomal abnormalities are the most important causes of mental retardation. Carriers of balanced chromosomal translocation are phenotypically normal, although they may be at risk of infertility, recurrent miscarriage or giving birth to mentally retarded children. These abnormalities are caused because chromosomes participated in the reciprocal translocations produce quadrivalents at meiosis. These quadrivalents segregate and lead to several different meiotic outcomes, just two of which are normal or balanced. Case Presentation: A consanguineous family with three mentally retarded daughters at the ages of 24, 18 and 10 years was referred to Comprehensive Medical Genetics Centre, Shiraz, Iran in 2015. Family history showed a case of unexplained infant death as well as a spontaneous abortion. Three survived siblings had hypotonia and severe developmental delay during infantile period. In addition, they suffer from primary amenorrhea. Two siblings have vesicoureteral reflux (VUR). Cytogenetic analysis of two patients showed 46,XX,t(6;12)(q23;q22),der(9)t(8;9)(q24;p24) with partial monosomy of chromosome 9 and partial trisomy of 8q24 segment, while the other patient had 46,XX,der(12)t(6;12)(q23;q22) with partial monosomy of 12q22qter and partial trisomy of 6q23qter segment. Their mother had two balanced chromosomal translocations (46, XX, t(6,12)(q21;q22), t(8,9)(q24;p24)). Conclusion: The above presented case is another example for the rare occurrence of double balanced chromosomal translocations in a phenotypically normal person. Although the most important causes of mental retardation in consanguineous marriages are autosomal recessive disorders, the role of chromosomal aberrations in mental retardation in these families must not be neglected. In other words, cytogenetic studies should be performed as a first line test in either situation

Autosomal recessive polycystic kidney disorder due to two novel compound heterozygote mutations in PKHD1 gene: case report

Background: Autosomal recessive polycystic kidney disorder (ARPCKD) is one of the most prevalent hereditary disorders in neonates and children. Its frequency is between 1/6000 to 1/55000 births. In the most severe cases, it can be diagnosed prenatally by the presence of enlarged, echogenic kidneys and oligohydramnios. However, in the milder forms, clinical manifestations are usually detected in neonatal and childhood period. PKHD1 gene located on chromosome 6 is linked with this disorder. About half of detected mutations in this gene are missense ones. The largest protein product of this gene is called the FPC/polyductin complex (FPC). It is a single-membrane spanning protein whose absence leads to abnormal ciliogenesis in the kidneys. Case presentation: Here we present a 5-year-old female patient affected with ARPCKD. She has been born to a non-consanguineous healthy Iranian parents. No similar disorder has been seen in the family. Prenatal history has been normal. In order to find the genetic background, DNA was extracted from patient's peripheral blood lymphocytes. PKHD1 gene exons and exon-intron boundaries were sequenced using next generation sequencing platform. Two novel variants have been detected in compound heterozygote state in the patient (c.6591C>A, c.8222C>A). Bioinformatics tools predicted these variants to be pathogenic. Conclusion: In the present study, we detected two novel variants in PKHD1 gene in a patient with ARPCKD. The relatively mild phenotype of this patient is in accordance with the missense mutations found. Molecular genetic tools can help in accurate risk assessment as well as precise genotype-phenotype correlation establishment in families affected with such disorder to decrease the birth of affected individuals through preimplantation genetic diagnosis or better management of disorder

Co-culture of Mouse Embryonic Stem Cells with Sertoli Cells Promote in vitro Generation of Germ Cells

  Objective(s): Sertoli cells support in vivo germ cell production; but, its exact mechanism has not been well understood. The present study was designed to analyze the effect of Sertoli cells in differentiation of mouse embryonic stem cells (mESCs) to germ cells.   Materials and Methods: A fusion construct composed of a Stra8 gene promoter and the coding region of enhanced green fluorescence protein was produced to select differentiated mESCs. To analyze sertoli cells’ effect in differentiation process, mESCs were separated into two groups: the first group was cultured on gelatin with retinoic acid treatment and the second group was co-cultured with sertoli cell feeder without retinoic acid induction. Expressions of pre-meiotic (Stra8), meiotic (Dazl and Sycp3) and post-meiotic (Prm1) genes were evaluated at different differentiation stages (+7, +12 and +18 days of culture). Results: In the first group, expressions of meiotic and post-meiotic genes started 12 and 18 days after induction with retinoic acid, respectively. In the second group, 7 days after co-culturing with Sertoli cells, expression of meiotic and post-meiotic genes was observed. Conclusion: These results show that differentiation process to germ cells is supported by Sertoli cells. Our findings provide a novel effective approach for generation of germ cell in vitro and studying the interaction of germ cells with their niche

Expression analysis of Tsga10 during in vitro differentiation of germ cells from mouse embryonic stem cell

Background: About 15% of couples have fertility problems and male factor in fertility accounts for half of the cases. In vitro generation of germ cells introduces a novel approach to male infertility and provides an effective system in gene tracking studies, however many aspects of this process have remained unclear. We aimed to promote mouse embryonic stem cells (mESCs) differentiation into germ cells and evaluate its effectiveness with tracking the expression of the Testis specific 10 (Tsga10) during this process. Methods: This is an in vitro study that was performed in department of Medical Genetics in Tehran University of Medical Sciences from February 2012 to March 2013. Mouse embryonic stem cells were cultured on mouse embryonic fibroblast as feeder layer. Then mESCs were differentiated into germ cells in the presence of Retinoic Acid. Based on developmental schedule of the postnatal testis, samples were taken on the 7th, 12th and 25th days of the culture and were subjected to expression analysis of a panel of germ cell specific genes (Stra8 as pre-meiotic, Dazl and Sycp3‌ as meiotic and Protamin1 and Spata19 as Post-meiotic). Expression of Testis Specific Gene 10 (Tsga10) at RNA and protein levels was then analyzed. Results: It was shown that transition of embryonic stem cells from mitosis to meiosis occurred between 7th and 12th days of mESC culture and post-meiotic gene expression did not occur until 25th day of the culture. Results showed low level of Tsga10 expression in undifferentiated stem cells. During transition from meiotic to post-meiotic phase, Tsga10 expression increased in 6.6 folds. This finding is in concordance with in vivo changes during transition from pre-pubertal to pubertal stage. Localization of processed and unprocessed form of the related protein was similar to those in vivo as well. Conclusion: Expression pattern of Tsga10, as a gene with critical function in spermatogenesis, is similar during in vitro and in vivo germ cell generation. The results suggest that in vitro derived germ cells could be a trusted model to study genes behavior during spermatogenesis