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Psychiatry and Clinical Neurosciences Aug 2017Elucidating the molecular basis of complex human psychiatric disorders is challenging due to the multitude of factors that underpin these disorders. Genetic and... (Review)
Review
Elucidating the molecular basis of complex human psychiatric disorders is challenging due to the multitude of factors that underpin these disorders. Genetic and chromosomal changes are two factors that have been suggested to be involved in psychiatric disorders. Indeed, numerous risk loci have been identified in autism spectrum disorders, schizophrenia, and related psychiatric disorders. Here, we introduce genetic animal models that disturb excitatory-inhibitory balance in the brain and animal models mirroring human chromosomal abnormalities, both of which may be implicated in autism spectrum disorder pathophysiology. In addition, we discuss recent unique translational research using rodent models, such as Cntnap2 knockout mouse, Mecp2 mutant mouse, Pick1 knockout mouse, and neonatal ventral hippocampal lesion rat. By using these models, several types of drugs are administered during the developmental period to see the effect on psychotic symptoms and neural activities in adults. The accumulating evidence from recent animal studies provides an informative intervention strategy as a translational research.
Topics: Animals; Chromosome Disorders; Disease Models, Animal; Early Medical Intervention; Mental Disorders
PubMed: 28317218
DOI: 10.1111/pcn.12524 -
Journal of Neurodevelopmental Disorders Jul 2021Phelan-McDermid syndrome (PMS) is a rare genetic disorder compromising the 22q13 terminal region and affecting SHANK3, a gene crucial to the neurobehavioural phenotype...
BACKGROUND
Phelan-McDermid syndrome (PMS) is a rare genetic disorder compromising the 22q13 terminal region and affecting SHANK3, a gene crucial to the neurobehavioural phenotype and strongly linked to autism (ASD) and intellectual disability (ID). The condition is characterised by global developmental delay, ID, speech impairments, hypotonia and autistic behaviours, although its presentation and symptom severity vary widely. In this study, we provide a thorough description of the behavioural profile in PMS and explore differences related to deletion size and language ability.
METHODS
We used standard clinical assessment instruments to measure altered behaviour, adaptive skills and autistic symptomatology in sixty participants with PMS (30 females, median age 8.5 years, SD=7.1). We recorded background information and other clinical manifestations and explored associations with deletion size. We performed descriptive and inferential analyses for group comparison.
RESULTS
We found delayed gross and fine motor development, delayed and impaired language (~70% of participants non or minimally verbal), ID of different degrees and adaptive functioning ranging from severe to borderline impairment. Approximately 40% of participants experienced developmental regression, and half of those regained skills. Autistic symptoms were frequent and variable in severity, with a median ADOS-2 CSS score of 6 for every domain. Sensory processing anomalies, hyperactivity, attentional problems and medical comorbidities were commonplace. The degree of language and motor development appeared to be associated with deletion size.
CONCLUSIONS
This study adds to previous research on the clinical descriptions of PMS and supports results suggesting wide variability of symptom severity and its association with deletion size. It makes the case for suitable psychotherapeutic and pharmacological approaches, for longitudinal studies to strengthen our understanding of possible clinical courses and for more precise genomic analysis.
Topics: Autism Spectrum Disorder; Child; Chromosome Deletion; Chromosome Disorders; Chromosomes, Human, Pair 22; Female; Humans; Phenotype
PubMed: 34246244
DOI: 10.1186/s11689-021-09370-5 -
Fertility and Sterility Jan 2017Embryonic mosaicism occurs when two or more cell populations with different genotypes are present within the same embryo. New diagnostic techniques for preimplantation... (Review)
Review
Embryonic mosaicism occurs when two or more cell populations with different genotypes are present within the same embryo. New diagnostic techniques for preimplantation genetic screening (PGS), such as next-generation sequencing, have led to increased reporting of mosaicism. The interpretation of mosaicism is complicated because the transfer of some mosaic embryos has resulted in live births. Mosaic embryos may represent a third category between normal (euploidy) and abnormal (aneuploidy). This category of mosaic embryos may be characterized by decreased implantation and pregnancy potential as well as increased risk of genetic abnormalities and adverse pregnancy outcomes. Euploid embryos should be preferentially transferred over mosaic embryos. Genetic counseling is necessary before the transfer of a mosaic embryo is considered. Certain types of mosaic embryos should be preferentially transferred over others. Transfer of embryos with mosaic trisomies 2, 7, 13, 14, 15, 16, 18, and 21 may pose the most risk of having a child affected with a trisomy syndrome; however, the transfer of embryos with mosaic monosomies or other mosaic trisomies are not devoid of risk. Patients must be counseled about the risk of undetected monosomies or trisomies within a biopsy specimen as well as the risk of intrauterine fetal demise or uniparental disomy with the transfer of mosaic embryos. Until more data are available, patients should be encouraged to undergo another cycle to obtain euploid embryos, when possible, rather than transferring a mosaic embryo.
Topics: Aneuploidy; Blastocyst; Chromosome Disorders; Chromosomes, Human; Embryo Transfer; Female; Genetic Counseling; Genetic Predisposition to Disease; Genetic Testing; Humans; Mosaicism; Phenotype; Predictive Value of Tests; Pregnancy; Pregnancy Outcome; Preimplantation Diagnosis; Reproductive Techniques, Assisted; Risk Assessment; Risk Factors; Treatment Outcome
PubMed: 27842993
DOI: 10.1016/j.fertnstert.2016.10.006 -
TheScientificWorldJournal 2022Worldwide, surveys have shown that the frequency of chromosomal disorders among births with congenital anomalies varies greatly from country to country. It is well known... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Worldwide, surveys have shown that the frequency of chromosomal disorders among births with congenital anomalies varies greatly from country to country. It is well known that chromosomal disorders are an important cause of premature death or life-long disability; however, the absence of local epidemiological data on their birth prevalence and outcomes impedes policy and service development in many countries and continents. Therefore, the current systematic review and meta-analysis intend to show the pooled proportion of chromosomal disorders among births with congenital anomalies in Africa.
METHODS
From PubMed, Cochrane Library, and Google Scholar, we systematically reviewed and meta-analyzed the studies that examined the incidence, prevalence, and types of chromosomal disorders using PRISMA guidelines. A weighted inverse variance random-effects model was used to estimate the pooled proportion of chromosomal disorders among births with congenital anomalies.
RESULTS
From the total of 3,569 studies identified, 1,442 were from PubMed, 108 were from Cochrane Library, 1,830 were from Google Scholar, and 189 were from other sources. After duplication was removed, a total of 844 articles remained (2725 were removed by duplication). Finally, 144 full-text studies were reviewed and 60 articles with 52,569 births having congenital anomalies met the inclusion criteria and were selected for this meta-analysis. The pooled proportion of chromosomal disorders among births with congenital anomalies was 8.94% (95% CI; 7.02, 10.86; = 98.8%; < 0.001). . In the current systematic review and meta-analysis, the pooled proportion of chromosomal disorders among births with congenital anomalies in Africa was small. Down syndrome (trisomy 21) accounted for more than 80% of chromosomal disorders. The pooled proportion of chromosome disorders was the highest in North African regions and countries compared to other regions of the continent. Healthcare managers should focus on establishing proper cytogenetic diagnostic facilities in collaboration with well-trained genetic counseling services in the continent.
Topics: Pregnancy; Female; Humans; Chromosome Disorders; Parturition; Prevalence; Africa; Incidence
PubMed: 36561944
DOI: 10.1155/2022/6477596 -
Fertility and Sterility May 2017The concept of embryos containing multiple cell lines (mosaicism) is not new, but much attention has been paid to this concept recently owing to recent advances in... (Review)
Review
The concept of embryos containing multiple cell lines (mosaicism) is not new, but much attention has been paid to this concept recently owing to recent advances in molecular techniques to analyze human embryos. Mosaicism in embryos has been known and reported for some time, originally in early cleavage-stage embryos diagnosed with the use of fluorescence in situ hybridization (FISH). However, the early data have come under attack owing to the limited ability of FISH to reliably detect the actual copy number count of chromosomes as well as potential ascertainment bias of those early studies, which were all performed on already analyzed embryos found to be aneuploid. More recent molecular techniques for analyzing embryos have allowed scientists to really begin to understand mosaic embryos, and to now transfer and follow this class of embryo. Indeed, it could be said that three classes of embryos now exist after preimplantation genetic screening: euploid, aneuploid, and mosaic aneuploid. This paper attempts to bring to light the latest data on mosaic embryos and to understand how clinicians and others will deal with this issue today and in the future. Finally, an attempt is made to look to other fields of genetics to understand how this important issue can be dealt with as a group much better than any one individual group may be able to.
Topics: Chromosome Disorders; Clinical Decision-Making; Embryo Implantation; Embryo Transfer; Evidence-Based Medicine; Female; Genetic Counseling; Genetic Testing; Humans; Mosaicism; Preimplantation Diagnosis
PubMed: 28476179
DOI: 10.1016/j.fertnstert.2017.03.016 -
European Journal of Medical Genetics Jul 2023Phelan-McDermid syndrome (PMS) is an infrequently described syndrome that presents with a disturbed development, neurological and psychiatric characteristics, and...
Phelan-McDermid syndrome (PMS) is an infrequently described syndrome that presents with a disturbed development, neurological and psychiatric characteristics, and sometimes other comorbidities. As part of the development of European medical guidelines we studied the definition, phenotype, genotype-phenotype characteristics, and natural history of the syndrome. The number of confirmed diagnoses of PMS in different European countries was also assessed and it could be concluded that PMS is underdiagnosed. The incidence of PMS in European countries is estimated to be at least 1 in 30,000. Next generation sequencing, including analysis of copy number variations, as first tier in diagnostics of individuals with intellectual disability will likely yield a larger number of individuals with PMS than presently known. A definition of PMS by its phenotype is at the present not possible, and therefore PMS-SHANK3 related is defined by the presence of SHANK3 haploinsufficiency, either by a deletion involving region 22q13.2-33 or a pathogenic/likely pathogenic variant in SHANK3. In summarizing the phenotype, we subdivided it into that of individuals with a 22q13 deletion and that of those with a pathogenic/likely pathogenic SHANK3 variant. The phenotype of individuals with PMS is variable, depending in part on the deletion size or whether only a variant of SHANK3 is present. The core phenotype in the domains development, neurology, and senses are similar in those with deletions and SHANK3 variants, but individuals with a SHANK3 variant more often are reported to have behavioural disorders and less often urogenital malformations and lymphedema. The behavioural disorders may, however, be a less outstanding feature in individuals with deletions accompanied by more severe intellectual disability. Data available on the natural history are limited. Results of clinical trials using IGF-1, intranasal insulin, and oxytocin are available, other trials are in progress. The present guidelines for PMS aim at offering tools to caregivers and families to provide optimal care to individuals with PMS.
Topics: Humans; DNA Copy Number Variations; Intellectual Disability; Nerve Tissue Proteins; Chromosome Disorders; Chromosome Deletion; Phenotype; Syndrome; Chromosomes, Human, Pair 22
PubMed: 37003575
DOI: 10.1016/j.ejmg.2023.104754 -
Journal of Neurodevelopmental Disorders Dec 2021The current study used eye tracking to investigate attention and recognition memory in Phelan-McDermid syndrome (PMS), a rare genetic disorder characterized by...
BACKGROUND
The current study used eye tracking to investigate attention and recognition memory in Phelan-McDermid syndrome (PMS), a rare genetic disorder characterized by intellectual disability, motor delays, and a high likelihood of comorbid autism spectrum disorder (ASD). Social deficits represent a core feature of ASD, including decreased propensity to orient to or show preference for social stimuli.
METHODS
We used a visual paired-comparison task with both social and non-social images, assessing looking behavior to a novel image versus a previously viewed familiar image to characterize social attention and recognition memory in PMS (n = 22), idiopathic ASD (iASD, n = 38), and typically developing (TD) controls (n = 26). The idiopathic ASD cohort was divided into subgroups with intellectual disabilities (ID; developmental quotient < 70) and without (developmental quotient > 70) and the PMS group into those with and without a co-morbid ASD diagnosis.
RESULTS
On measures of attention, the PMS group with a comorbid ASD diagnosis spent less time viewing the social images compared to non-social images; the rate of looking back and forth between images was lowest in the iASD with ID group. Furthermore, while all groups demonstrated intact recognition memory when novel non-social stimuli were initially presented (pre-switch), participants with PMS showed no preference during the post-switch memory presentation. In iASD, the group without ID, but not the group with ID, showed a novelty preference for social stimuli. Across indices, individuals with PMS and ASD performed more similarly to PMS without ASD and less similarly to the iASD group.
CONCLUSION
These findings demonstrate further evidence of differences in attention and memory for social stimuli in ASD and provide contrasts between iASD and PMS.
Topics: Attention; Autism Spectrum Disorder; Chromosome Deletion; Chromosome Disorders; Chromosomes, Human, Pair 22; Eye-Tracking Technology; Humans
PubMed: 34863106
DOI: 10.1186/s11689-021-09400-2 -
Deutsches Arzteblatt International Dec 2010Prenatal diagnosis is a subfield of clinical genetics and gynecology that exemplifies the effective integration of theoretical and clinical medicine. Milestones in its... (Review)
Review
BACKGROUND
Prenatal diagnosis is a subfield of clinical genetics and gynecology that exemplifies the effective integration of theoretical and clinical medicine. Milestones in its history include the development of cytogenetic, molecular genetic, and molecular cytogenetic methods as well as advances in ultrasonography. The latter technique not only improves the safety of invasive procedures, but also enables earlier and more reliable diagnosis of congenital malformations.
METHODS
This article provides an overview of the subject in the light of selectively reviewed literature, guidelines, and recommendations.
RESULTS AND CONCLUSION
Invasive prenatal diagnosis is most commonly performed to assess the embryonal/fetal chromosome set. An increasing number of monogenic diseases can be diagnosed prenatally by either genetic or biochemical testing, depending on the particular disease being sought. Polygenic and multifactorial diseases cannot be reliably diagnosed by genetic testing at present, although a number of malformations can be ascertained prenatally by ultrasonography. We discuss the applications and limitations of invasive and noninvasive techniques for prenatal diagnosis.
Topics: Chromosome Disorders; Female; Genetic Testing; Humans; Male; Prenatal Diagnosis
PubMed: 21173933
DOI: 10.3238/arztebl.2010.0857 -
Genetics and Molecular Research : GMR Oct 2014The accuracy of prenatal diagnosis for abnormal chromosome diseases by chromosome microarray technology and karyotyping were compared. A literature search was carried... (Review)
Review
The accuracy of prenatal diagnosis for abnormal chromosome diseases by chromosome microarray technology and karyotyping were compared. A literature search was carried out in the MEDLINE database with the keywords "chromosome" and "karyotype" and "genetic testing" and "prenatal diagnosis" and "oligonucleotide array sequence". The studies obtained were filtered by using the QUADAS tool, and studies conforming to the quality standard were fully analyzed. There was one paper conforming to the QUADAS standards including 4406 gravidas with adaptability syndromes of prenatal diagnosis including elderly parturient women, abnormal structure by type-B ultrasound, and other abnormalities. Microarray technology yielded successful diagnoses in 4340 cases (98.8%), and there was no need for tissue culture in 87.9% of the samples. All aneuploids and non-parallel translocations in 4282 cases of non-chimera identified by karyotyping could be detected using microarray analysis technology, whereas parallel translocations and fetal triploids could not be detected by microarray analysis technology. In the samples with normal karyotyping results, type-B ultrasound showed that 6% of chromosomal deficiencies or chromosome duplications could be detected by microarray technology, and the same abnormal chromosomes were detected in 1.7% of elderly parturient women and samples with positive serology screening results. In the prenatal diagnosis test, compared with karyotyping, microarray technology could identify the extra cell genetic information with clinical significance, aneuploids, and non-parallel translocations; however, its disadvantage is that it could not identify parallel translocations and triploids.
Topics: Chromosome Disorders; Female; Fetal Diseases; Humans; Karyotyping; Microarray Analysis; Pregnancy; Prenatal Diagnosis; Reproducibility of Results; Sensitivity and Specificity
PubMed: 25366803
DOI: 10.4238/2014.October.31.27 -
Orphanet Journal of Rare Diseases Nov 2008The inv dup(15) or idic(15) syndrome displays distinctive clinical findings represented by early central hypotonia, developmental delay and intellectual disability,... (Review)
Review
The inv dup(15) or idic(15) syndrome displays distinctive clinical findings represented by early central hypotonia, developmental delay and intellectual disability, epilepsy, and autistic behaviour. Incidence at birth is estimated at 1 in 30,000 with a sex ratio of almost 1:1. Developmental delay and intellectual disability affect all individuals with inv dup(15) and are usually moderate to profound. Expressive language is absent or very poor and often echolalic. Comprehension is very limited and contextual. Intention to communicate is absent or very limited. The distinct behavioral disorder shown by children and adolescents has been widely described as autistic or autistic-like. Epilepsy with a wide variety of seizure types can occur in these individuals, with onset between 6 months and 9 years. Various EEG abnormalities have been described. Muscle hypotonia is observed in almost all individuals, associated, in most of them, with joint hyperextensibility and drooling. Facial dysmorphic features are absent or subtle, and major malformations are rare. Feeding difficulties are reported in the newborn period.Chromosome region 15q11q13, known for its instability, is highly susceptible to clinically relevant genomic rearrangements, such as supernumerary marker chromosomes formed by the inverted duplication of proximal chromosome 15. Inv dup(15) results in tetrasomy 15p and partial tetrasomy 15q. The large rearrangements, containing the Prader-Willi/Angelman syndrome critical region (PWS/ASCR), are responsible for the inv dup(15) or idic(15) syndrome. Diagnosis is achieved by standard cytogenetics and FISH analysis, using probes both from proximal chromosome 15 and from the PWS/ASCR. Microsatellite analysis on parental DNA or methylation analysis on the proband DNA, are also needed to detect the parent-of-origin of the inv dup(15) chromosome. Array CGH has been shown to provide a powerful approach for identifying and detecting the extent of the duplication. The possible occurrence of double supernumerary isodicentric chromosomes derived from chromosome 15, resulting in partial hexasomy of the maternally inherited PWS/ASCR, should be considered in the differential diagnosis. Large idic(15) are nearly always sporadic. Antenatal diagnosis is possible. Management of inv dup(15) includes a comprehensive neurophysiologic and developmental evaluation. Survival is not significantly reduced.
Topics: Abnormalities, Multiple; Adult; Child; Child, Preschool; Chromosome Aberrations; Chromosome Disorders; Chromosome Inversion; Chromosomes, Human, Pair 15; Female; Humans; In Situ Hybridization, Fluorescence; Infant; Intellectual Disability; Male; Seizures; Syndrome
PubMed: 19019226
DOI: 10.1186/1750-1172-3-30