scholarly journals Consequences of 22q11.2 Microdeletion on the Genome, Individual and Population Levels

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 977
Author(s):  
Małgorzata Karbarz

Chromosomal 22q11.2 deletion syndrome (22q11.2DS) (ORPHA: 567) caused by microdeletion in chromosome 22 is the most common chromosomal microdeletion disorder in humans. Despite the same change on the genome level, like in the case of monozygotic twins, phenotypes are expressed differently in 22q11.2 deletion individuals. The rest of the genome, as well as epigenome and environmental factors, are not without influence on the variability of phenotypes. The penetrance seems to be more genotype specific than deleted locus specific. The transcript levels of deleted genes are not usually reduced by 50% as assumed due to haploinsufficiency. 22q11.2DS is often an undiagnosed condition, as each patient may have a different set out of 180 possible clinical manifestations. Diverse dysmorphic traits are present in patients from different ethnicities, which makes diagnosis even more difficult. 22q11.2 deletion syndrome serves as an example of a genetic syndrome that is not easy to manage at all stages: diagnosis, consulting and dealing with.

Genetika ◽  
2016 ◽  
Vol 48 (1) ◽  
pp. 57-72
Author(s):  
Marijana Rakonjac ◽  
Goran Cuturilo ◽  
Milena Stevanovic ◽  
Ida Jovanovic ◽  
Ljiljana Jelicic-Dobrijevic ◽  
...  

The 22q11.2 Deletion Syndrome (22q11.2DS), which encompasses Shprintzen syndrome, DiGeorge and velocardiofacial syndrome, is the most common microdeletion syndrome in humans with an estimated incidence of approximately 1/4000 per live births. After Down syndrome, it is the second most common genetic syndrome associated with congenital heart malformations. The mode of inheritance of the 22q11.2DS is autosomal dominant. In approximately 72 - 94% of the cases the deletion has occurred de novo, while in 6 to 28% of patients deletion was inherited from a parent. As a part of a multidisciplinary study we examined the speech and language abilities of members of two families with inherited form of 22q11.2DS. The presence of 22q11.2 microdeletion was revealed by fluorescence in situ hybridization (FISH) and/or multiplex ligation-dependent probe amplification (MLPA). In one family we detected 1.5 Mb 22q11.2 microdeletion, while in the other family we found 3Mb microdeletion. Patients from both families showed delays in cognitive, socio-emotional, speech and language development. Furthermore, we found considerable variability in the phenotypic characteristics of 22q11.2DS and the degree of speech-language pathology not only between different families with 22q11.2 deletion, but also among members of the same family. In addition, we detected no correlation between the phenotype and the size of 22q11.2 microdeletion.


2021 ◽  
Vol 23 (6) ◽  
pp. 1357-1366
Author(s):  
D. A. Cheremokhin ◽  
S. S. Deryabina ◽  
I. A. Tuzankina ◽  
E. V. Vlasova ◽  
N. V. Nikitina ◽  
...  

Chromosomal pathology is one of the most common causes of congenital malformations. The CATCH-22 symptom complex is most often associated with a microdeletion of chromosome 22, upon detection of which it is customary to diagnose DiGeorge syndrome, a known primary immunodeficiency or syndrome of innate errors of immunity. According to our data on the frequency of occurrence among all chromosomal abnormalities, DiGeorge’s syndrome takes second place in the Sverdlovsk region after Down’s syndrome, but its diagnosis is not simple due to varying severity of clinical manifestations, as well as different forms of the chromosome 22 defects. Along with several typical variants of 22q11 microdeletions, there duplications of critical regions are also reported, accompanied by immunodeficiency and other symptoms of CATCH-22. The effectiveness of diagnosing chromosomal abnormalities both in pre- and postnatal period largely depends on the grouping criteria of the patients with suspected chromosomal abnormalities, and on the methods used to identify hereditary pathology. In our study, we analyzed and compared the results of studies of 23 patients with various rearrangements of the 22q11.2 region, which were observed by a geneticist and clinical immunologist. The paper presents data on the polymorphism of phenotypes associated with rearrangements of the 22q11.2 region with an analysis of pathomorphological manifestations depending on the type of structural anomaly, i.e, del22q11.2, or dup22q11.2. The results of analysis demonstrate importance of different diagnostic options for laboratory studies of microdeletion and microduplication syndromes associated with immune-dependent pathology. We also compared the results of molecular genetic diagnostics and phenotypic manifestations in deletions and duplications of the 22q11.2 region. To identify the rearrangements of 22q11.2 region, two different methods were used – Prenatal BoBs and multiplex ligase-dependent probes’ amplification (MLPA). In particular, the both methods were used in the same patient to verify diagnosis, thus enabling to show differences in their efficiency. It was concluded that 22q11.2 deletion syndrome exhibits wide heterogeneity in phenotypic traits: neurological and immunological manifestations, anomalies in musculoskeletal development and internal organs, skull deformities and facial dysmorphia. Each clinical case was unique, requiring careful analysis of clinical manifestations. It is necessary to have a wide range of laboratory options for molecular genetic verification of the diagnosis.


2018 ◽  
Vol 2018 ◽  
pp. 1-3
Author(s):  
A. Bahji ◽  
S. Khalid-Khan

22q11.2 duplication syndrome is a recently discovered genetic syndrome with unclear neuropsychiatric sequelae. While its connection to 22q11.2 deletion syndrome is actively investigated, case reports on the neuropsychiatric sequelae of affected individuals have been previously described, largely focusing on comorbid autism spectrum disorder. Here, we present the case of an 8-year-old female experiencing episodes of severe behavioural regression following medical illness. We analyze the case and relate it to the available literature and identify potential risk factors.


2018 ◽  
Vol 48 (1) ◽  
pp. 20-26 ◽  
Author(s):  
R. Weinberger ◽  
O. Weisman ◽  
Y. Guri ◽  
T. Harel ◽  
A. Weizman ◽  
...  

AbstractBackgroundThe 22q11.2 deletion syndrome (22q11DS) is the most common genetic syndrome associated with schizophrenia. The goal of this study was to evaluate longitudinally the interaction between neurocognitive functioning, the presence of subthreshold psychotic symptoms (SPS) and conversion to psychosis in individuals with 22q11DS. In addition, we attempted to identify the specific neurocognitive domains that predict the longitudinal evolution of positive and negative SPS, as well as the effect of psychiatric medications on 22q11DS psychiatric and cognitive developmental trajectories.MethodsForty-four participants with 22q11DS, 19 with Williams syndrome (WS) and 30 typically developing (TD) controls, age range 12–35 years, were assessed at two time points (15.2 ± 2.1 months apart). Evaluation included the Structured Interview for Prodromal Symptoms (SIPS), structured psychiatric evaluation and the Penn Computerized Neurocognitive Battery (CNB).Results22q11DS individuals with SPS had a yearly conversion rate to psychotic disorders of 8.8%, compared to none in both WS and TD controls. Baseline levels of negative SPS were associated with global neurocognitive performance (GNP), executive function and social cognition deficits, in individuals with 22q11DS, but not in WS. Deficits in GNP predicted negative SPS in 22q11DS and the emergence or persistence of negative SPS. 22q11DS individuals treated with psychiatric medications showed significant improvement in GNP score between baseline and follow-up assessments, an improvement that was not seen in untreated 22q11DS.ConclusionsOur results highlight the time-dependent interplay among positive and negative SPS symptoms, neurocognition and pharmacotherapy in the prediction of the evolution of psychosis in 22q11DS.


Neurology ◽  
2001 ◽  
Vol 57 (3) ◽  
pp. 410-416 ◽  
Author(s):  
W. D. Graf ◽  
A. S. Unis ◽  
C. M. Yates ◽  
S. Sulzbacher ◽  
M. B. Dinulos ◽  
...  

Objective: To investigate catecholamine phenotypes and the effects of a tyrosine hydroxylase inhibitor in individuals with the 22q11.2 deletion syndrome and low-activity catechol-O-methyltransferase (COMT).Background: Many persons with the 22q11.2 deletion syndrome suffer severe disability from a characteristic ultrarapid-cycling bipolar disorder and associated “affective storms.” One etiologic hypothesis for this condition is that deletion of the COMT gene from one chromosome 22 results in increased catecholamine neurotransmission, particularly if the undeleted chromosome 22 encodes a variant of COMT with low activity.Methods: In a preliminary study, plasma, urine, and CSF catecholamines and catecholamine metabolites were measured in four teenage patients with a neuropsychiatric condition associated with 22q11.2 deletion and the low-activity COMT polymorphism on the nondeleted chromosome. In these four patients, and an additional institutionalized adult with the condition, an uncontrolled, open-label trial of metyrosine was administered in an attempt to lower catecholamine production and to alleviate symptoms.Results: Mild elevations of baseline CSF homovanillic acid (HVA) were found in three of four patients and a moderate reduction in CSF HVA after metyrosine treatment in the patient with the highest pretreatment concentration. The course of the five patients during the clinical trial is described.Conclusions: In patients with the 22q11.2 deletion syndrome and low-activity COMT, controlled studies of pharmacologic agents that decrease catecholamine production, block presynaptic catecholamine storage, or enhance S-adenosylmethionine, the cosubstrate of COMT, are warranted.


2021 ◽  
Author(s):  
Isabela Mayá Wayhs Silva ◽  
Vera Lúcia Gil-da-Silva-Lopes

Abstract Background: 22q11.2 Deletion Syndrome (22q11.2DS) is a rare disease that has as an important characteristic the clinical heterogeneity. The diversity of organs, regions, and systems of the body that can be affected requires periodic updating of health professionals so that they can recognize this clinical signs as belonging to 22q11.2DS. Updated health professionals are equally important for the appropriate and timely establishment of clinical management for individuals with a positive diagnosis. In this context, this article aimed to map and analyse the access to health care for individuals with 22q11.2DS until the moment of diagnosis. Results: We analysed clinical data of 111 individuals with 22q11.2DS registered in the Brazilian Database on Craniofacial Anomalies (BDCA) from 2008 to 2020. In this study, individuals were diagnosed with a median age of 9 years (mean = 9.7 years). Before genetic investigation, they accessed 68.75% of the international recommended evaluations available at BDCA. Recurrent 22q11.2DS clinical manifestations as delayed neuropsychomotor development, lip and/or palate defects, cardiac malformation and/or hematological/immunological alteration co-occurred in at least 72.06% of individuals. Cardiac malformation was the only clinical alteration that led to a lower median diagnostic age, corresponding to 6.5 years of age with a cardiac malformation versus 11 years of age without a cardiac malformation (p = 0.0006). Conclusions: In Brazil, 22q11.2 DS is under recognized and early diagnosis and management of affected individuals are still a distant reality. In this sense, the identification followed by the correction of obstacles that do not allow this reality are essential to increase life expectancy and improve the quality of life of these individuals in Brazil


2020 ◽  
Author(s):  
Maria Gudbrandsen ◽  
Anke Bletsch ◽  
Caroline Mann ◽  
Eileen Daly ◽  
Clodagh M Murphy ◽  
...  

Abstract Background: A crucial step to understanding the mechanistic underpinnings of autism spectrum disorder (ASD), is to examine if the biological underpinnings of ASD in genetic high-risk conditions, like 22q11.2 Deletion Syndrome (22q11.2DS), are similar to those in idiopathic illness. This study aimed to examine if ASD symptomatology in 22q11.2DS is underpinned by the same – or distinct – neural systems that mediate these symptoms in non-deletion carriers. Methods: We examined vertex-wise estimates of cortical volume (CV), surface area (SA), and cortical thickness across 131 individuals between 6 and 25 years of age including (1) 50 individuals with 22q11.2DS, out of which n=25 had a diagnosis of ASD, (2) 40 non-carriers of the microdeletion with a diagnosis of ASD (i.e. idiopathic ASD), and (3) 41 typically developing (TD) controls. We employed a 2-by-2 factorial design to identify neuroanatomical variability associated with the main effects of 22q11.2DS and ASD, as well as their interaction. Further, using canonical correlation analysis (CCA), we compared neuroanatomical variability associated with the complex (i.e. multivariate) clinical phenotype of ASD between 22q11.2 deletion carriers and non-carriers. Results: The set of brain regions associated with the main effect of 22q11.2DS was distinct from the neuroanatomical underpinnings of the main effect of ASD. Moreover, significant 22q11.2DS-by-ASD interactions were observed for CV and SA in the dorsolateral prefrontal cortex, precentral gyrus, and posterior cingulate cortex, suggesting that the neuroanatomy of ASD is significantly modulated by 22q11.2DS ( p <0.01). We further established that the multivariate patterns of neuroanatomical variability associated with differences in symptom profiles significantly differed between 22q11.2 deletion carriers and non-carriers. Limitations: We employed a multicenter design to overcome single-site recruitment limitations, however, FreeSurfer derived measures of surface anatomy have been shown to be highly reliable across scanner platforms and field-strengths’. Further, we controlled for gender to address the differing distribution between idiopathic ASD individuals and the other groups. Nonetheless, the gender distribution in our sample reflects that of the respective populations, adding to the generalizability of our results. Last, we included individuals with a relatively wide age range (i.e. 6-25 years). Conclusions: Our findings indicate that neuroanatomical correlates of ASD symptomatology in carriers of the 22q11.2 microdeletion diverge from those in idiopathic ASD.


Author(s):  
Maria Cabrer ◽  
Guillermo Serra ◽  
María Soledad Gogorza ◽  
Vicente Pereg

Summary Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a genetic syndrome that may present with hypocalcemia due to primary hypoparathyroidism (PH) at any age. We report a new diagnosis of 22q11.2DS in a 57-year-old man who presented with symptomatic hypocalcemia. It is important to consider genetic causes of hypocalcemia due to PH regardless of age. Learning points: It is important to discard genetic cause of primary hypoparathyroidism in a patient without autoimmune disease or prior neck surgery. A new diagnosis of a hereditary disease has familial implications and needs genetic counselling. It is also important to discard other syndrome’s comorbidities.


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