1
|
Gao K, Zhang Y, Zhang L, Kong W, Xie H, Wang J, Wu Y, Wu X, Liu X, Zhang Y, Zhang F, Yu ACH, Jiang Y. Large De Novo Microdeletion in Epilepsy with Intellectual and Developmental Disabilities, with a Systems Biology Analysis. ADVANCES IN NEUROBIOLOGY 2018; 21:247-266. [DOI: 10.1007/978-3-319-94593-4_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
2
|
Moreira DP, Griesi-Oliveira K, Bossolani-Martins AL, Lourenço NCV, Takahashi VNO, da Rocha KM, Moreira ES, Vadasz E, Meira JGC, Bertola D, Halloran EO, Magalhães TR, Fett-Conte AC, Passos-Bueno MR. Investigation of 15q11-q13, 16p11.2 and 22q13 CNVs in autism spectrum disorder Brazilian individuals with and without epilepsy. PLoS One 2014; 9:e107705. [PMID: 25255310 PMCID: PMC4177849 DOI: 10.1371/journal.pone.0107705] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 08/21/2014] [Indexed: 11/18/2022] Open
Abstract
Copy number variations (CNVs) are an important cause of ASD and those located at 15q11-q13, 16p11.2 and 22q13 have been reported as the most frequent. These CNVs exhibit variable clinical expressivity and those at 15q11-q13 and 16p11.2 also show incomplete penetrance. In the present work, through multiplex ligation-dependent probe amplification (MLPA) analysis of 531 ethnically admixed ASD-affected Brazilian individuals, we found that the combined prevalence of the 15q11-q13, 16p11.2 and 22q13 CNVs is 2.1% (11/531). Parental origin could be determined in 8 of the affected individuals, and revealed that 4 of the CNVs represent de novo events. Based on CNV prediction analysis from genome-wide SNP arrays, the size of those CNVs ranged from 206 kb to 2.27 Mb and those at 15q11-q13 were limited to the 15q13.3 region. In addition, this analysis also revealed 6 additional CNVs in 5 out of 11 affected individuals. Finally, we observed that the combined prevalence of CNVs at 15q13.3 and 22q13 in ASD-affected individuals with epilepsy (6.4%) was higher than that in ASD-affected individuals without epilepsy (1.3%; p<0.014). Therefore, our data show that the prevalence of CNVs at 15q13.3, 16p11.2 and 22q13 in Brazilian ASD-affected individuals is comparable to that estimated for ASD-affected individuals of pure or predominant European ancestry. Also, it suggests that the likelihood of a greater number of positive MLPA results might be found for the 15q13.3 and 22q13 regions by prioritizing ASD-affected individuals with epilepsy.
Collapse
MESH Headings
- Adolescent
- Base Sequence
- Brazil
- Child
- Child Development Disorders, Pervasive/complications
- Child Development Disorders, Pervasive/genetics
- Chromosomes, Human/genetics
- Chromosomes, Human, Pair 15/genetics
- Chromosomes, Human, Pair 16/genetics
- Chromosomes, Human, Pair 22/genetics
- DNA Copy Number Variations
- Epilepsy/complications
- Female
- Genomics
- Humans
- Male
- Pedigree
- Polymorphism, Single Nucleotide
Collapse
Affiliation(s)
- Danielle P. Moreira
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Karina Griesi-Oliveira
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Ana L. Bossolani-Martins
- Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, SP, Brasil
| | - Naila C. V. Lourenço
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Vanessa N. O. Takahashi
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Kátia M. da Rocha
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Eloisa S. Moreira
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Estevão Vadasz
- Instituto de Psiquiatria do Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brasil
| | - Joanna Goes Castro Meira
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Debora Bertola
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
- Instituto da Criança da Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brasil
| | - Eoghan O’ Halloran
- Academic Centre on Rare Diseases, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Tiago R. Magalhães
- Academic Centre on Rare Diseases, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
- National Children’s Research Centre, Our Lady’s Children’s Hospital, Dublin, Ireland
| | - Agnes C. Fett-Conte
- Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, SP, Brasil
| | - Maria Rita Passos-Bueno
- Centro de Pesquisas sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| |
Collapse
|
3
|
Chen Y, Parker WD, Wang K. The role of T-type calcium channel genes in absence seizures. Front Neurol 2014; 5:45. [PMID: 24847307 PMCID: PMC4023043 DOI: 10.3389/fneur.2014.00045] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 03/24/2014] [Indexed: 12/05/2022] Open
Abstract
The thalamic relay neurons, reticular thalamic nucleus, and neocortical pyramidal cells form a circuit that sustains oscillatory burst firing, and is regarded as the underlying mechanism of absence seizures. T-type calcium channels play a key role in this circuit. Here, we review the role of T-type calcium channel genes in the development of absence seizures, and emphasize gain or loss of function mutations, and other variations that alter both quantity and quality of transcripts, and methylation status of isoforms of T-type calcium channel proteins might be of equal importance in understanding the pathological mechanism of absence seizures.
Collapse
Affiliation(s)
- Yucai Chen
- University of Illinois at Chicago , Peoria, IL , USA
| | | | - Keling Wang
- Hebei Children Hospital , Shijiazhuang , China
| |
Collapse
|
4
|
Cooper DN, Krawczak M, Polychronakos C, Tyler-Smith C, Kehrer-Sawatzki H. Where genotype is not predictive of phenotype: towards an understanding of the molecular basis of reduced penetrance in human inherited disease. Hum Genet 2013; 132:1077-130. [PMID: 23820649 PMCID: PMC3778950 DOI: 10.1007/s00439-013-1331-2] [Citation(s) in RCA: 423] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/15/2013] [Indexed: 02/06/2023]
Abstract
Some individuals with a particular disease-causing mutation or genotype fail to express most if not all features of the disease in question, a phenomenon that is known as 'reduced (or incomplete) penetrance'. Reduced penetrance is not uncommon; indeed, there are many known examples of 'disease-causing mutations' that fail to cause disease in at least a proportion of the individuals who carry them. Reduced penetrance may therefore explain not only why genetic diseases are occasionally transmitted through unaffected parents, but also why healthy individuals can harbour quite large numbers of potentially disadvantageous variants in their genomes without suffering any obvious ill effects. Reduced penetrance can be a function of the specific mutation(s) involved or of allele dosage. It may also result from differential allelic expression, copy number variation or the modulating influence of additional genetic variants in cis or in trans. The penetrance of some pathogenic genotypes is known to be age- and/or sex-dependent. Variable penetrance may also reflect the action of unlinked modifier genes, epigenetic changes or environmental factors. At least in some cases, complete penetrance appears to require the presence of one or more genetic variants at other loci. In this review, we summarize the evidence for reduced penetrance being a widespread phenomenon in human genetics and explore some of the molecular mechanisms that may help to explain this enigmatic characteristic of human inherited disease.
Collapse
Affiliation(s)
- David N. Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN UK
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Christian-Albrechts University, 24105 Kiel, Germany
| | | | - Chris Tyler-Smith
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | | |
Collapse
|
5
|
Rozycka A, Dorszewska J, Steinborn B, Lianeri M, Winczewska-Wiktor A, Sniezawska A, Wisniewska K, Jagodzinski PP. Association study of the 2-bp deletion polymorphism in exon 6 of the CHRFAM7A gene with idiopathic generalized epilepsy. DNA Cell Biol 2013; 32:640-7. [PMID: 24024466 DOI: 10.1089/dna.2012.1880] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is evidence of linkage between the 15q13-q14 locus, containing the gene encoding the α7 subunit (CHRNA7) of the neuronal nicotinic acetylcholine receptor (nAChR) and its partially duplicated isoform (CHRFAM7A), and epilepsy. Additionally, a 2-bp deletion polymorphism (c.497-498delTG; rs67158670) in CHRFAM7A, resulting in a frame shift and truncation of the protein product, is associated with some neurological diseases. This study was designed to explore the possibility of an association of the c.497-498delTG polymorphism of CHRFAM7A with idiopathic generalized epilepsies (IGEs) in Polish children and young patients. The study included 197 IGE patients and 258 unrelated healthy individuals. The frequency of the CHRFAM7A c.497-498delTG polymorphism was determined in each group using heteroduplex analysis. An association between the c.497-498delTG polymorphism of CHRFAM7A and IGE was evidenced. It was demonstrated that the frequency of the CHRFAM7A 2-bp deletion carriers was significantly lower in the IGE patients than in the control group. The observed frequency of 2-bp deletion carriers was high in IGE subjects (64%), but significantly higher in control subjects (76%). Carriers of at least one copy of the -2 bp allele had halved their risk of IGE susceptibility (delTG/delTG and delTG/wild-type versus wild-type/wild-type: odds ratio=0.55; 95% confidence intervals=0.365-0.827; p=0.004). Moreover, it has been demonstrated that this polymorphic variant is associated with the c.524-12_524-11insGTT variation (rs10649395) in intron 7 of CHRFAM7A. Our study substantiates the involvement of the α7 subunit of nAChR in the pathophysiology of IGEs and indicates that the CHRFAM7A c.497-498TG deletion or a nearby polymorphism may play a role in the pathogenesis of IGE. Further work should concentrate on ascertaining the exact mechanism of this polymorphism's effect and its relationship with IGE.
Collapse
Affiliation(s)
- Agata Rozycka
- 1 Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences , Poznan, Poland
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Coppola A, Bagnasco I, Traverso M, Brusco A, Di Gregorio E, Del Gaudio L, Santulli L, Caccavale C, Vigliano P, Minetti C, Striano S, Zara F, Striano P. Different electroclinical picture of generalized epilepsy in two families with 15q13.3 microdeletion. Epilepsia 2013; 54:e69-73. [PMID: 23448223 DOI: 10.1111/epi.12130] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2013] [Indexed: 12/18/2022]
Abstract
15q.13.3 microdeletion has been described in a variety of neurodevelopmental disorders. Epilepsy appears to be a common feature and, specifically, the 15q13.3 microdeletion is found in about 1% of patients with idiopathic generalized epilepsy. Recently, absence seizures with intellectual disability (ID) have been reported in patients carrying this mutation. We describe two families in which several affected members carry a 15q13.3 microdeletion in a pattern suggestive of autosomal dominant inheritance. Their phenotype includes mainly absence epilepsy and mild ID, suggesting only similarities with genetic/idiopathic generalized epilepsies but not typical features. The importance of studying such families is crucial to broaden the phenotype and understand the long-term outcome of patients with this condition.
Collapse
Affiliation(s)
- Antonietta Coppola
- Epilepsy Center, Neurology Department, Federico II University of Naples, Naples, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Lal D, Trucks H, Møller RS, Hjalgrim H, Koeleman BPC, de Kovel CGF, Visscher F, Weber YG, Lerche H, Becker F, Schankin CJ, Neubauer BA, Surges R, Kunz WS, Zimprich F, Franke A, Illig T, Ried JS, Leu C, Nürnberg P, Sander T. Rare exonic deletions of the RBFOX1 gene increase risk of idiopathic generalized epilepsy. Epilepsia 2013; 54:265-71. [PMID: 23350840 DOI: 10.1111/epi.12084] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2012] [Indexed: 01/13/2023]
Abstract
PURPOSE Structural variations disrupting the gene encoding the neuron-specific splicing regulator RBFOX1 have been reported in three patients exhibiting epilepsy in comorbidity with other neuropsychiatric disorders. Consistently, the Rbfox1 knockout mouse model showed an increased susceptibility of seizures. The present candidate gene study tested whether exon-disrupting deletions of RBFOX1 increase the risk of idiopathic generalized epilepsies (IGEs), representing the largest group of genetically determined epilepsies. METHODS Screening of microdeletions (size: >40 kb, coverage >20 markers) affecting the genomic sequence of the RBFOX1 gene was carried out by high-resolution single-nucleotide polymorphism (SNP) arrays in 1,408 European patients with idiopathic generalized epilepsy (IGE) and 2,256 population controls. Validation of RBFOX1 deletions and familial segregation analysis were performed by quantitative polymerase chain reaction (qPCR). KEY FINDINGS We detected five exon-disrupting RBFOX1 deletions in the IGE patients, whereas none was observed in the controls (p = 0.008, Fisher's exact test). The size of the exonic deletions ranged from 68 to 896 kb and affected the untranslated 5'-terminal RBFOX1 exons. Segregation analysis in four families indicated that the deletions were inherited, display incomplete penetrance, and heterogeneous cosegregation patterns with IGE. SIGNIFICANCE Rare deletions affecting the untranslated 5'-terminal RBFOX1 exons increase risk of common IGE syndromes. Variable expressivity, incomplete penetrance, and heterogeneous cosegregation patterns suggest that RBFOX1 deletions act as susceptibility factor in a genetically complex etiology, where heterogeneous combinations of genetic factors determine the disease phenotype.
Collapse
Affiliation(s)
- Dennis Lal
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|