|
|
Cryptic Rearrangements of Human Chromosomes Associated with Autism Spectrum Disorders
Křivánková, Anna ; Šolc, Roman (advisor) ; Růžičková, Šárka (referee)
Autism spectrum disorders (ASD) are heterogeneous group of neurodevelopmental disabilities characterized by antisociality and atypical behavioral patterns. Its etiology is very complex, autism is usually formed by combining many factors. One of the causes may be genetic (gene mutation). It is known about 450 candidate genes for ASD so far. Minority of these genes occur in loci which are affected by cryptic rearrangements. These rearrangements significantly contribute to manifestation of this disorder. Patologies they cause, lead to syndromes with high penetrance for ASD such as Angelman/Prader-Willi or DiGeorge syndrome. Other loci are found on chromosome 1, 2 or 16. Due to short time of studies of cryptic rearrangements, phenotypic variability and number of patients we can expect more researches in the future. These researches are expected not to overlook the impact of the aberrations on formation of autism spectrum disorders.
|
|
|
Molecular Genetic Analysis in Patients Suspected of Cryptic Rearrangements.
Šolc, Roman ; Hirschfeldová, Kateřina (advisor) ; Vícha, Aleš (referee)
Such chromosomal rearrangements, which cannot be detected by using of cytogenetic banding of metaphase chromosomes, i.e. chromosomes smaller than 3 - 5 Mb, and therefore modern molecular genetic methods are used to detect them, are called "cryptic rearrangements". Their important role in human pathology is more and more significant. By using of the multiplex ligation-probe dependent amplification method (MLPA) we examined a group of 50 probands with idiopathic mental retardation. A cryptic rearrangement was found at 8 probands (16 %), at 6 of them it was demonstrably causal. Then we examined a group of 40 probands suspected of gene SHOX pathology. A cryptic rearrangement was found at 17 probands (42.5 %) and at 8 of them it was demonstrably causal. Presence of small deletion founded isolated at 7 probands was verified in a population set, but without a positive result. An analysis of mutations was made too.
|
|
|
The significance of the parental origin of the affected chromosome in the development of microdeletion syndromes
Rašpličková, Tereza ; Šolc, Roman (advisor) ; Novotná, Drahuše (referee)
Microdeletion syndromes are complex diseases caused by loss of genetic information resulting from cryptic deletions which are smaller than 5 Mb. They are cause a large number of phenotypic features. Most common are developmental and mental retardations, various physical defects and abnormalities or behavior problems. It has been shown, that in some cases plays a role parental origin of affected chromosome in microdeletion syndrome. In Angelman, Prader-Willi and Beckwith-Wiedemann syndromes is unequal disability of chromosomes caused by genomic imprinting. The reasons for dominance disability of one parental chromosome in Cri du chat syndrome, monosomy 1p36 and Phelan-McDermid syndrome are different and the effect of genomic imprinting has not been confirmed. Key words: microdeletion, microdeletion syndromes, methylation, genomic imprinting
|
|
|
Cryptic Rearrangements of Human Chromosomes Associated with Autism Spectrum Disorders
Křivánková, Anna ; Šolc, Roman (advisor) ; Růžičková, Šárka (referee)
Autism spectrum disorders (ASD) are heterogeneous group of neurodevelopmental disabilities characterized by antisociality and atypical behavioral patterns. Its etiology is very complex, autism is usually formed by combining many factors. One of the causes may be genetic (gene mutation). It is known about 450 candidate genes for ASD so far. Minority of these genes occur in loci which are affected by cryptic rearrangements. These rearrangements significantly contribute to manifestation of this disorder. Patologies they cause, lead to syndromes with high penetrance for ASD such as Angelman/Prader-Willi or DiGeorge syndrome. Other loci are found on chromosome 1, 2 or 16. Due to short time of studies of cryptic rearrangements, phenotypic variability and number of patients we can expect more researches in the future. These researches are expected not to overlook the impact of the aberrations on formation of autism spectrum disorders.
|
|
|
Microduplications on human chromosomes
Štolová, Lucie ; Šolc, Roman (advisor) ; Brynychová, Iva (referee)
Microduplications are small chromosomal aberrations, for whose detection it is necessary to use molecular cytogenetic methods (FISH, CGH) instead of common cytogenetic methods. Together with microdeletions, they are most often mediated by non-allelic homologous recombination during meiosis. They occur at many places in human genome and the duplications of some chromosomal regions are responsible for syndrome emergence. Some of the genes, that are included by microduplications, are dosage sensitive and they cause the pathological phenotype. As a result of development of molecular genetic methods and their usage in studies targeted on microduplications, it comes out, that presence of microduplications on the human chromosomes was undervalued, especially because of their minor clinical significance compared to microdeletions.
|
|
|
The significance of the parental origin of the affected chromosome in the development of microdeletion syndromes
Rašpličková, Tereza ; Šolc, Roman (advisor) ; Novotná, Drahuše (referee)
Microdeletion syndromes are complex diseases caused by loss of genetic information resulting from cryptic deletions which are smaller than 5 Mb. They are cause a large number of phenotypic features. Most common are developmental and mental retardations, various physical defects and abnormalities or behavior problems. It has been shown, that in some cases plays a role parental origin of affected chromosome in microdeletion syndrome. In Angelman, Prader-Willi and Beckwith-Wiedemann syndromes is unequal disability of chromosomes caused by genomic imprinting. The reasons for dominance disability of one parental chromosome in Cri du chat syndrome, monosomy 1p36 and Phelan-McDermid syndrome are different and the effect of genomic imprinting has not been confirmed. Key words: microdeletion, microdeletion syndromes, methylation, genomic imprinting
|
|
|
Reciprocal microdeletion and microduplication on human chromosomes
Sluková, Lucie ; Šolc, Roman (advisor) ; Brynychová, Iva (referee)
Nonallelic homologous recombination (NAHR) mediated by LCRs (low-copy repeats) produces chromosomal rearrangements in the human genome. Those rearrangements include microdeletion and microduplication. Those mutations cause a great number of syndromes and thus are studied along with its genesis. Studies are enabled by the development of methods, which are able to detect those cryptic aberrations, e.g. comparative genomic hybridisation (CGH). Nowadays scientists often come across the mirror phenotype of the already described microdeletion (microduplication) syndromes. The presence of the reciprocal microduplication (microdeletion), which afflicted a gene sensitive to gene dosage or other important region of the human genome, is discovered by a genomic analysis. The examples of those affected chromosomal regions (and associated diseases) are areas 1q21.1; 5q35.2-3 (Sotos syndrome); 7q11.23 (Williams-Beuren syndrome); 16p11.2 až 12.2 a 16p13.11; 17q11.2 (Neurofibromatosis type 1); 17p11.2-12 (CMT1A/HNPP) a 22q11.2 (DiGeorge syndrome and VCFS). Key words: microduplication; microdeletion; nonallelic homologous recombination (NAHR); comparative genomic hybridisation (CGH); mirror phenotype; reciprocal rearrangements.
|
|
|
Molecular Genetic Analysis in Patients Suspected of Cryptic Rearrangements.
Šolc, Roman ; Hirschfeldová, Kateřina (advisor) ; Vícha, Aleš (referee)
Such chromosomal rearrangements, which cannot be detected by using of cytogenetic banding of metaphase chromosomes, i.e. chromosomes smaller than 3 - 5 Mb, and therefore modern molecular genetic methods are used to detect them, are called "cryptic rearrangements". Their important role in human pathology is more and more significant. By using of the multiplex ligation-probe dependent amplification method (MLPA) we examined a group of 50 probands with idiopathic mental retardation. A cryptic rearrangement was found at 8 probands (16 %), at 6 of them it was demonstrably causal. Then we examined a group of 40 probands suspected of gene SHOX pathology. A cryptic rearrangement was found at 17 probands (42.5 %) and at 8 of them it was demonstrably causal. Presence of small deletion founded isolated at 7 probands was verified in a population set, but without a positive result. An analysis of mutations was made too.
|
guest ::
