Premature death in adults with 22q11.2 deletion syndrome

Multicenter appraisal of comorbid TANGO2 deficiency disorder in patients with 22q11.2 deletion syndrome

TANGO2 deficiency disorder (TDD) is a rare, autosomal recessive condition caused by pathogenic variants in TANGO2, a gene residing within the region commonly deleted in 22q11.2 deletion syndrome (22q11.2DS). Although patients with 22q11.2DS are at substantially higher risk for comorbid TDD, it remains underdiagnosed within 22q11.2DS, likely due to overlapping symptomatology and a lack of knowledge about TDD. Initiation of B-vitamin supplementation may provide therapeutic benefit in TDD, highlighting the need for effective screening methods to improve diagnosis rates in this at-risk group. In this retrospective, multicenter study, we evaluated two cohorts of patients with 22q11.2DS (total N = 435) for possible comorbid TDD using two different symptom-based screening methods (free text-mining and manual chart review versus manual chart review alone). The methodology of the cohort 1 screening method successfully identified a known 22q11.2DS patient with TDD. Combined, these two cohorts identified 21 living patients meeting the consensus recommendation for TANGO2 testing for suspected comorbid TDD. Of the nine patients undergoing TANGO2 sequencing with del/dup analysis, none were ultimately diagnosed with TDD. Of the 12 deaths in the suspected comorbid TDD cohort, some of these patients exhibited symptoms (rhabdomyolysis, cardiac arrhythmia, or metabolic crisis) suspicious of comorbid TDD contributing to their death. Collectively, these findings highlight the need for robust prospective screening tools for diagnosing comorbid TDD in patients with 22q11.2DS.

Chromosome 22q11.2 Deletion (DiGeorge Syndrome): Immunologic Features, Diagnosis, and Management

PURPOSE OF REVIEW

This review focuses on immunologic findings, relationships among immunologic findings and associated conditions of autoimmunity and atopy, and management of immunologic disease in chromosome 22q11.2 deletion syndrome (22q11.2DS, historically known as DiGeorge syndrome).

RECENT FINDINGS

The implementation of assessment of T cell receptor excision circles (TRECs) in newborn screening has led to increased detection of 22q11.2 deletion syndrome. While not yet applied in clinical practice, cell-free DNA screening for 22q11.2DS also has the potential to improve early detection, which may benefit prompt evaluation and management. Multiple studies have further elucidated phenotypic features and potential biomarkers associated with immunologic outcomes, including the development of autoimmune disease and atopy. The clinical presentation of 22q11.2DS is highly variable particularly with respect to immunologic manifestations. Time to recovery of immune system abnormalities is not well-defined in current literature. An understanding of the underlying causes of immunologic changes found in 22q11.2DS, and the progression and evolution of immunologic changes over the lifespan have expanded over time and with improved survival. An included case highlights the variability of presentation and potential severity of T cell lymphopenia in partial DiGeorge syndrome and demonstrates successful spontaneous immune reconstitution in partial DiGeorge syndrome despite initial severe T cell lymphopenia.

Coexisting Conditions Modifying Phenotypes of Patients with 22q11.2 Deletion Syndrome

22q11.2 deletion syndrome (22q11.2DS) is the most common genomic disorder with an extremely broad phenotypic spectrum. The aim of our study was to investigate how often the additional variants in the genome can affect clinical variation among patients with the recurrent deletion. To examine the presence of additional variants affecting the phenotype, we performed microarray in 82 prenatal and 77 postnatal cases and performed exome sequencing in 86 postnatal patients with 22q11.2DS. Within those 159 patients where array was performed, 5 pathogenic and 5 likely pathogenic CNVs were identified outside of the 22q11.2 region. This indicates that in 6.3% cases, additional CNVs most likely contribute to the clinical presentation. Additionally, exome sequencing in 86 patients revealed 3 pathogenic (3.49%) and 5 likely pathogenic (5.81%) SNVs and small CNV. These results show that the extension of diagnostics with genome-wide methods can reveal other clinically relevant changes in patients with 22q11 deletion syndrome.

Short-term Prognostic Value of Heart Failure Diagnosis in a Contemporary Cohort of Patients With Adult Congenital Heart Disease

BACKGROUND

Heart failure (HF) is the primary cause of premature death in adult congenital heart disease (ACHD). This study aimed to describe the impact of a HF diagnosis on short-term prognosis and to investigate the added prognostic value of an HF diagnosis to the ACHD Anatomic and Physiologic classification (ACHD-AP).

METHODS

This study included 3995 patients followed in a tertiary care centre (last follow-up after January 1, 2010). Survival curves were plotted, and predictors of the primary end point (death, heart transplantation, or ventricular assist device [VAD]) were identified with the use of Cox proportional hazard models and compared with the use of Harrell's C-statistic.

RESULTS

Mean age at baseline was 35.7 ± 13.3 years. The prevalence of ACHD-HF was 6.4%. During a median follow-up of 3.1 years (IQR 2.1-3.6 years), 27.3% of ACHD-HF patients reached the primary end point, compared with 1.4% of ACHD patients without HF. Event-free survivals were 78.3%, 61.9%, and 57.5% at 1, 3, and 5 years in ACHD-HF patients, compared with 99.3%, 98.3%, and 98.0% in ACHD patients without HF (P < 0.001). An HF diagnosis (HR 6.9, 95% CI 4.3-11.2) and the physiologic classification (HR 2.6, 95% CI 1.9-3.7) were independently associated with the primary end point. The addition of HF to the ACHD-AP classification yielded a Harrell's C-index of 0.8631, providing a significant improvement over the ACHD-AP classification alone (P = 0.0003).

CONCLUSIONS

The risk of mortality, transplantation, or VAD is increased in ACHD-HF patients. An HF diagnosis appears to be a valuable prognostic marker in addition to the ACHD-AP classification.

Updated clinical practice recommendations for managing adults with 22q11.2 deletion syndrome

This review aimed to update the clinical practice guidelines for managing adults with 22q11.2 deletion syndrome (22q11.2DS). The 22q11.2 Society recruited expert clinicians worldwide to revise the original clinical practice guidelines for adults in a stepwise process according to best practices: (1) a systematic literature search (1992-2021), (2) study selection and synthesis by clinical experts from 8 countries, covering 24 subspecialties, and (3) formulation of consensus recommendations based on the literature and further shaped by patient advocate survey results. Of 2441 22q11.2DS-relevant publications initially identified, 2344 received full-text review, with 2318 meeting inclusion criteria (clinical care relevance to 22q11.2DS) including 894 with potential relevance to adults. The evidence base remains limited. Thus multidisciplinary recommendations represent statements of current best practice for this evolving field, informed by the available literature. These recommendations provide guidance for the recognition, evaluation, surveillance, and management of the many emerging and chronic 22q11.2DS-associated multisystem morbidities relevant to adults. The recommendations also address key genetic counseling and psychosocial considerations for the increasing numbers of adults with this complex condition.

Hypoparathyroidism and late-onset hypogonadism in an adult male with familial 22q11.2 deletion syndrome: a case report with 3-year follow-up and review of the literature

BACKGROUND

22q11.2 deletion syndrome (DiGeorge syndrome) is associated with multiple organ dysfunctions such as cardiac defects, immunodeficiency, and hypoplasia of parathyroid glands. Moreover, the phenotype of 22q11.2 DS has clinical variability and heterogeneity.

CASE PRESENTATION

In this report, we present the case of a 35-year-old patient with a past medical history that included recurrent infections, mild learning difficulties in childhood, pediatric obesity, and cataract. He was admitted to the endocrinology department for the management of hypogonadism and hypocalcemia. During the 3-year follow-up, the patient gradually developed primary hypoparathyroidism, hypogonadism, chronic renal failure, and heart failure, and his medical condition deteriorated. Meanwhile, in order to improve clinicians' awareness of the endocrine manifestations of adult 22q11.2 DS and reduce missed diagnoses, we reviewed 28 case reports of adult 22q11.2 DS to analyze the clinical characteristics.

DISCUSSION

Here, we report the case of a young man diagnosed with 22q11.2 DS presented a rare combination of multiple endocrine disorders. This is the first time that a patient with 22q11.2DS had late-onset hypogonadism caused by primary testicular failure combined with decreased pituitary gonadotropin reserve in a patient with 22q11.2DS.

Different Types of Deletions Created by Low-Copy Repeats Sequences Location in 22q11.2 Deletion Syndrome: Genotype-Phenotype Correlation

The most frequent microdeletion, 22q11.2 deletion syndrome (22q11.2DS), has a wide and variable phenotype that causes difficulties in diagnosis. 22q11.2DS is a contiguous gene syndrome, but due to the existence of several low-copy-number repeat sequences (LCR) it displays a high variety of deletion types: typical deletions LCR A-D-the most common (~90%), proximal deletions LCR A-B, central deletions (LCR B, C-D) and distal deletions (LCR D-E, F).

METHODS

We conducted a retrospective study of 59 22q11.2SD cases, with the aim of highlighting phenotype-genotype correlations. All cases were tested using MLPA combined kits: SALSA MLPA KIT P245 and P250 (MRC Holland).

RESULTS

most cases (76%) presented classic deletion LCR A-D with various severity and phenotypic findings. A total of 14 atypical new deletions were identified: 2 proximal deletions LCR A-B, 1 CES (Cat Eye Syndrome region) to LCR B deletion, 4 nested deletions LCR B-D and 1 LCR C-D, 3 LCR A-E deletions, 1 LCR D-E, and 2 small single gene deletions: delDGCR8 and delTOP3B.

CONCLUSIONS

This study emphasizes the wide phenotypic variety and incomplete penetrance of 22q11.2DS. Our findings contribute to the genotype-phenotype data regarding different types of 22q11.2 deletions and illustrate the usefulness of MLPA combined kits in 22q11.2DS diagnosis.

Cardiac function in adolescents and young adults with 22q11.2 deletion syndrome without congenital heart disease

BACKGROUND

Diagnosis and treatment of 22q11.2 deletion syndrome (22q11.2DS) have led to improved life expectancy and achievement of adulthood. Limited data on long-term outcomes reported an increased risk of premature death for cardiovascular causes, even without congenital heart disease (CHD). The aim of this study was to assess the cardiac function in adolescents and young adults with 22q11.2DS without CHDs.

METHODS

A total of 32 patients (20M, 12F; mean age 26.00 ± 8.08 years) and a healthy control group underwent transthoracic echocardiography, including Tissue Doppler Imaging (TDI) and 2-dimensional Speckle Tracking Echocardiography (2D-STE).

RESULTS

Compared to controls, 22q11.2DS patients showed a significant increase of the left ventricle (LV) diastolic and systolic diameters (p = 0.029 and p = 0.035 respectively), interventricular septum thickness (p = 0.005), LV mass index (p < 0.001) and aortic root size (p < 0.001). 2D-STE analysis revealed a significant reduction of LV global longitudinal strain (p < 0.001) in 22q11.2DS than controls. Moreover, several LV diastolic parameters were significantly different between groups.

CONCLUSIONS

Our results suggest that an echocardiographic follow-up in 22q11.2DS patients without CHDs can help to identify subclinical impairment of the LV and evaluate a potential progression of aortic root dilation over time, improving outcomes, reducing long-term complications and allowing for a better prognosis.

Multiple Intestinal Anomalies in a Newborn with 22q11.2 Microdeletion Syndrome: A Case Report and Literature Review

Although 40 years have passed since the first case of DiGeorge's syndrome was described, and the knowledge about this disorder has steadily increased since that time, 22q11.2 deletion syndrome (DS) remains a challenging diagnosis because its clinical presentation varies widely. We describe an infant with 22q11.2 DS who presented with annular pancreas, anorectal malformation, Morgagni-type congenital diaphragmatic hernia, and ventricular septal defect. This constellation of anomalies has never been described in DiGeorge's syndrome. Here, we provide a case presentation and a thorough review of the literature.

Spectrum of Genetic T-Cell Disorders from 22q11.2DS to CHARGE

Improved genetic testing has led to recognition of a diverse group of disorders of inborn errors of immunity that present as primarily T-cell defects. These disorders present with variable degrees of immunodeficiency, autoimmunity, multiple organ system dysfunction, and neurocognitive defects. 22q11.2 deletion syndrome, commonly known as DiGeorge syndrome, represents the most common disorder on this spectrum. In most individuals, a 3 Mb deletion of 22q11 results in haploinsufficiency of 90 known genes and clinical complications of varying severity. These include cardiac, endocrine, gastrointestinal, renal, palatal, genitourinary, and neurocognitive anomalies. Multidisciplinary treatment also includes pediatrics/general practitioners, genetic counseling, surgery, interventional therapy, and psychology/psychiatry. Chromosome 10p deletion, TBX1 mutation, CHD7 mutation, Jacobsen syndrome, and FOXN1 deficiency manifest with similar overlapping clinical presentations and T-cell defects. Recognition of the underlying disorder and pathogenesis is essential for improved outcomes. Diagnosing and treating these heterogenous conditions are a challenge and rapidly improving with new diagnostic tools. Collectively, these disorders are an example of the complex penetrance and severity of genetic disorders, importance of translational diagnostics, and a guide for multidisciplinary treatment.

22q11.2 Deletion Syndrome: Impact of Genetics in the Treatment of Conotruncal Heart Defects

Congenital heart diseases represent one of the hallmarks of 22q11.2 deletion syndrome. In particular, conotruncal heart defects are the most frequent cardiac malformations and are often associated with other specific additional cardiovascular anomalies. These findings, together with extracardiac manifestations, may affect perioperative management and influence clinical and surgical outcome. Over the past decades, advances in genetic and clinical diagnosis and surgical treatment have led to increased survival of these patients and to progressive improvements in postoperative outcome. Several studies have investigated long-term follow-up and results of cardiac surgery in this syndrome. The aim of our review is to examine the current literature data regarding cardiac outcome and surgical prognosis of patients with 22q11.2 deletion syndrome. We thoroughly evaluate the most frequent conotruncal heart defects associated with this syndrome, such as tetralogy of Fallot, pulmonary atresia with major aortopulmonary collateral arteries, aortic arch interruption, and truncus arteriosus, highlighting the impact of genetic aspects, comorbidities, and anatomical features on cardiac surgical treatment.

Clinical Manifestations of 22q11.2 Deletion Syndrome

DiGeorge syndrome (DGS), also known as "22q11.2 deletion syndrome" (22q11DS) (MIM # 192430 # 188400), is a genetic disorder caused by hemizygous microdeletion of the long arm of chromosome 22. In the last decades, the introduction of fluorescence in situ hybridization assays, and in selected cases the use of multiplex ligation-dependent probe amplification, has allowed the detection of chromosomal microdeletions that could not be previously identified using standard karyotype analysis. The aim of this review is to address cardiovascular and systemic involvement in children with DGS, provide genotype-phenotype correlations, and discuss their medical management and therapeutic options.

Rare Diseases of the Oral Cavity, Neck, and Pharynx

Diseases occurring with an incidence of less than 1-10 cases per 10 000 individuals are considered as rare. Currently, between 5 000 and 8 000 rare or orphan diseases are known, every year about 250 rare diseases are newly described. Many of those pathologies concern the head and neck area. In many cases, a long time is required to diagnose an orphan disease. The lives of patients who are affected by those diseases are often determined by medical consultations and inpatient stays. Most orphan diseases are of genetic origin and cannot be cured despite medical progress. However, during the last years, the perception of and the knowledge about rare diseases has increased also due to the fact that publicly available databases have been created and self-help groups have been established which foster the autonomy of affected people. Only recently, innovative technical progress in the field of biogenetics allows individually characterizing the genetic origin of rare diseases in single patients. Based on this, it should be possible in the near future to elaborate tailored treatment concepts for patients suffering from rare diseases in the sense of translational and personalized medicine. This article deals with orphan diseases of the lip, oral cavity, pharynx, and cervical soft tissues depicting these developments. The readers will be provided with a compact overview about selected diseases of these anatomical regions. References to further information for medical staff and affected patients support deeper knowledge and lead to the current state of knowledge in this highly dynamic field.

Effectiveness and side effects of psychopharmacotherapy in individuals with 22q11.2 deletion syndrome with comorbid psychiatric disorders: a systematic review

22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion in humans and is associated with high rates of attention deficit/hyperactivity disorder (ADHD), psychotic spectrum disorders and mood and anxiety disorders. The objective of the study was to systematically review studies regarding pharmacological treatments for psychiatric disorders in individuals with 22q11.2DS and to provide practical guidelines for the psychiatric management and side effect monitoring in 22q11.2DS. A literature search was conducted using the databases PubMed, PsycINFO and Embase. Information regarding study population, drug treatment, side effect profile and efficacy for each trial was extracted. Data collection was completed on May 2018. The search identified 705 studies. A total of seven studies, describing 182 individuals, were included. Pharmacological interventions included three studies for antipsychotic treatment, two studies for stimulants, one study for selective serotonin reuptake inhibitors (SSRIs), one study for S-adenosyl-L-methionine (SAMe), and one case series for metyrosine. The presented data support the clinical impression that individuals with 22q11.2DS and comorbid psychiatric disorders are treated in a manner comparable to non-22q11.2DS individuals. However, distinct medical comorbidities common in individuals with 22q11.2DS may complicate the administration of pharmacotherapy. Further trials with RCT design, larger sample sizes and more syndrome-specific pharmacological agents are needed to improve evidence-based psychiatric care of 22q11.2DS individuals with comorbid mental disorders.

Prenatal screening of DiGeorge (22q11.2 deletion) syndrome by abnormalities of the great arteries among Thai pregnant women

Objective

22q11.2DS (deletion syndrome) is one of the common serious anomalies resulting in high perinatal morbidity and mortality rate. Nevertheless, prenatal diagnosis of 22q11.2DS in Southeast Asia has never been described and its prevalence in prenatal series has never been explored. The objective of this study was to describe the experience of prenatal diagnosis of 22q11.2DS in the Thai population and to determine its prevalence among fetuses prenatally diagnosed with abnormalities of the great arteries.

Methods

A prospective study was conducted on pregnant Thai women prenatally diagnosed with abnormalities of the great arteries in the second trimester. The recruited cases were investigated for fetal 22q11.2 deletion by in situ hybridization with a probe specific to the DiGeorge/VCFS TUPLE 1 region located on chromosome 22 for the locus D22S75, and 22qter for a telomere specific sequence clone as the control region.

Results

Five out of the 42 (11.9%) fetuses with abnormalities of the great arteries meeting the inclusion criteria were proven to have 22q11.2DS. The most common abnormalities were the tetralogy of Fallot (or variants) and right-sided aortic arch, followed by a thymic hypoplasia.

Conclusion

As observed in the western countries, we have documented that, among pregnant Thai women, 22q11.2DS is highly prevalent in fetuses with abnormalities of the great arteries (approximately 12%). This information is important when counselling couples to undergo prenatal testing for 22q11.2DS, since this information is vital in the patients' decision of termination or continuation of pregnancy and in a well-prepared management of the affected child.

22q11.2 deletion syndrome is associated with increased mortality in adults with tetralogy of Fallot and pulmonary atresia with ventricular septal defect

BACKGROUND

22q11.2 Deletion syndrome (22q11.2DS) is common in patients with tetralogy of Fallot (TOF) or pulmonary atresia with ventricular septal defect (PA/VSD) and is associated with worse outcomes in children. Whether this impaired prognosis is also translated into adulthood is unknown, as data in adult patients are limited. We aimed to compare long-term outcomes in adults with TOF or PA/VSD both with and without 22q11.2DS.

METHODS

This study prospectively followed a nationwide multicenter cohort of TOF or PA/VSD patients with genetically confirmed presence or absence of 22q11.2DS, from inclusion in the Dutch national CONCOR registry for adults with congenital heart disease (CHD) onward. Outcome measures included all-cause mortality, cardiac mortality, need for pulmonary valve replacement (PVR), ventricular arrhythmias (VA), pacemaker implantation, and ICD implantation.

RESULTS

In total, 479 patients were included (277 (58%) male, median age 28 [IQR; 21-37] years, 62 (13%) with PA/VSD, 34 (7%) with 22q11.2DS). During a median follow-up of 11 [IQR; 6-13] years, 52 (11%) patients died (8 with 22q11.2DS and 44 without 22q11.2DS). Patients with 22q11.2DS had significant decreased survival after 12 years (76% [95% CI; 62-93]) compared to patients without 22q11.2DS (89% [95% CI; 86-92], p = 0.008). 22q11.2DS was associated with increased risk of all-cause mortality and cardiac-mortality, independent of age, sex, and PA/VSD. No association was found between 22q11.2DS and late complications i.e. PVR, VA, pacemaker, or ICD implantation.

CONCLUSIONS

Adults with TOF or PA/VSD with 22q11.2DS have a significantly worse survival than adults without this deletion. In patients with TOF or PA/VSD, genetic analysis for the presence of 22q11.2DS is important for risk stratification and genetic counseling.

The Genetics and Epigenetics of 22q11.2 Deletion Syndrome

Chromosome 22q11.2 deletion syndrome (22q11.2del) is a complex, multi-organ disorder noted for its varying severity and penetrance among those affected. The clinical problems comprise congenital malformations; cardiac problems including outflow tract defects, hypoplasia of the thymus, hypoparathyroidism, and/or dysmorphic facial features. Additional clinical issues that can appear over time are autoimmunity, renal insufficiency, developmental delay, malignancy and neurological manifestations such as schizophrenia. The majority of individuals with 22q11.2del have a 3 Mb deletion of DNA on chromosome 22, leading to a haploinsufficiency of ~106 genes, which comprise coding RNAs, noncoding RNAs, and pseudogenes. The consequent haploinsufficiency of many of the coding genes are well described, including the key roles of T-box Transcription Factor 1 (TBX1) and DiGeorge Critical Region 8 (DGCR8) in the clinical phenotypes. However, the haploinsufficiency of these genes alone cannot account for the tremendous variation in the severity and penetrance of the clinical complications among those affected. Recent RNA and DNA sequencing approaches are uncovering novel genetic and epigenetic differences among 22q11.2del patients that can influence disease severity. In this review, the role of coding and non-coding genes, including microRNAs (miRNA) and long noncoding RNAs (lncRNAs), will be discussed in relation to their bearing on 22q11.2del with an emphasis on TBX1.

What is new with 22q? An update from the 22q and You Center at the Children's Hospital of Philadelphia

22q11.2 deletion syndrome (22q11.2DS) is a disorder caused by recurrent, chromosome-specific, low copy repeat (LCR)-mediated copy-number losses of chromosome 22q11. The Children's Hospital of Philadelphia has been involved in the clinical care of individuals with what is now known as 22q11.2DS since our initial report of the association with DiGeorge syndrome in 1982. We reviewed the medical records on our continuously growing longitudinal cohort of 1,421 patients with molecularly confirmed 22q11.2DS from 1992 to 2018. Most individuals are Caucasian and older than 8 years. The mean age at diagnosis was 3.9 years. The majority of patients (85%) had typical LCR22A-LCR22D deletions, and only 7% of these typical deletions were inherited from a parent harboring the deletion constitutionally. However, 6% of individuals harbored other nested deletions that would not be identified by traditional 22q11.2 FISH, thus requiring an orthogonal technology to diagnose. Major medical problems included immune dysfunction or allergies (77%), palatal abnormalities (67%), congenital heart disease (64%), gastrointestinal difficulties (65%), endocrine dysfunction (>50%), scoliosis (50%), renal anomalies (16%), and airway abnormalities. Median full-scale intelligence quotient was 76, with no significant difference between individuals with and without congenital heart disease or hypocalcemia. Characteristic dysmorphic facial features were present in most individuals, but dermatoglyphic patterns of our cohort are similar to normal controls. This is the largest longitudinal study of patients with 22q11.2DS, helping to further describe the condition and aid in diagnosis and management. Further surveillance will likely elucidate additional clinically relevant findings as they age.

22q11 microdeletion syndrome and ultra-high risk for psychosis: The role of neurological soft signs as an independent marker of vulnerability for psychosis

AIM

22q11 microdeletion syndrome has an increased risk for psychosis, similar to subjects at ultra-high risk for psychosis. Neurological soft signs are considered an endophenotype of psychotic disorders and a marker of vulnerability to Schizophrenia, consisting of overflow movements, dysrhythmia and speed of timed activities. To date, there are no studies that have evaluated the presence of the neurological soft signs in subjects with 22q11 microdeletion syndrome and there are a few studies that have analysed this issue in subjects at ultra-high risk.

METHODS

We sought to measure neurological soft signs in these two conditions, compared to healthy controls and to analyse the possible correlation between neurological soft signs and positive/negative symptoms both in 22q11 microdeletion syndrome and ultra-high-risk groups. 54 drug-naive patients (29 with 22q11 microdeletion syndrome and 25 at ultra-high risk for psychosis) and 25 healthy controls were evaluated for neurological soft signs.

RESULTS

Both clinical groups showed a greater number of neurological soft signs compared to healthy control, although the two clinical groups did not differ for the number of neurological soft signs. Positive correlation between speed of timed activities and negative symptoms was found in subjects at ultra-high risk.

CONCLUSION

Neurological soft signs could represent a marker of atypical neurodevelopment in the two populations examined. Since we did not found a strong correlation between neurological soft signs and positive/negative symptoms, we suggest that neurological soft signs could be indicators of vulnerability to psychosis independent from the psychopathology.

All-cause mortality and survival in adults with 22q11.2 deletion syndrome

Purpose

Given limited data available on long-term outcomes in 22q11.2 deletion syndrome (22q11.2DS), we investigated mortality risk in adults with this microdeletion syndrome.

Methods

We studied 309 well-characterized adults (age ≥17 years) with 22q11.2DS and their 1014 unaffected parents and siblings, using a prospective case–control design. We used Cox proportional hazards regression modeling and Kaplan–Meier curves to investigate effects of the 22q11.2 deletion and its associated features on all-cause mortality and survival.

Results

The 22q11.2 deletion (hazard ratio [HR] 8.86, 95% CI 2.87–27.37) and major congenital heart disease (CHD; HR 5.03, 95% CI 2.27–11.17), but not intellectual disability or psychotic illness, were significant independent predictors of mortality for adults with 22q11.2DS compared with their siblings. Amongst those with 22q11.2DS, there were 31 deaths that occurred at a median age of 46.4 (range 18.1–68.6) years; a substantial minority had outlived both parents. Probability of survival to age 45 years was approximately 72% for those with major CHD, and 95% for those with no major CHD (p < 0.0001).

Conclusion

For adults with 22q11.2DS, the 22q11.2 deletion and more severe forms of CHD both contribute to a lower life expectancy than family-based expectations. The results have implications for genetic counseling and anticipatory care.

22q11.2 Deletion Syndrome-Associated Parkinson's Disease

Background

22q11.2 deletion syndrome (22q11.2DS) is a multisystem condition associated with an increased risk of early‐onset Parkinson's disease (PD).

Methods

We review the clinical, neuroimaging, and neuropathological observations, as well as diagnostic challenges, of PD in 22q11.2DS. We conducted a search of PubMed up until June 1, 2018 and personal files to identify relevant publications.

Results

22q11.2DS‐associated PD is responsible for approximately 0.5% of early‐onset PD. The hallmark motor symptoms and neuropathology of PD, and typical findings of reduced striatal dopamine transporter binding with molecular imaging, are present in 22q11.2DS‐associated PD. Mean age at PD onset in 22q11.2DS is relatively young (∼40 years). Patients with 22q11.2DS‐associated PD show a good response to levodopa.

Conclusions

Further recognition of 22q11.2DS and study of PD in people with 22q11.2DS could provide insights into the mechanisms that cause PD in the general population. 22q11.2DS may serve as an identifiable PD model to study prodromal PD and disease‐modifying treatments.

Neuropsychiatric expression and catatonia in 22q11.2 deletion syndrome: An overview and case series

Individuals with 22q11.2 deletion syndrome (22q11.2DS) are at elevated risk of developing treatable psychiatric and neurological disorders, including anxiety disorders, schizophrenia, seizures, and movement disorders, often beginning in adolescence or early to mid-adulthood. Here, we provide an overview of neuropsychiatric features associated with 22q11.2DS in adulthood. Results of a new case series of 13 individuals with 22q11.2DS and catatonic features together with 5 previously reported cases support a potential association of this serious psychomotor phenotype with the 22q11.2 deletion. As in the general population, catatonic features in 22q11.2DS occurred in individuals with schizophrenia, other psychotic and non-psychotic psychiatric disorders, and neurological disorders like Parkinson's disease. We place the results in the context of an updated review of catatonia in other genetic conditions. The complex neuropsychiatric expression and risk profile of 22q11.2DS highlights the need to consider co-morbid factors and provide care tailored to the individual patient. The results reinforce the need for periodic monitoring for the emergence of psychiatric and neurological manifestations including catatonic features. Pending further research, enhanced recognition and informed anticipatory care promise to facilitate the early diagnosis that allows for timely implementation and optimization of effective treatments.

Defective Vagal Innervation in Murine Tbx1 Mutant Hearts

Haploinsufficiency of the T-box transcription factor TBX1 is responsible for many features of 22q11.2 deletion syndrome. Tbx1 is expressed dynamically in the pharyngeal apparatus during mouse development and Tbx1 homozygous mutants display numerous severe defects including abnormal cranial ganglion formation and neural crest cell defects. These abnormalities prompted us to investigate whether parasympathetic (vagal) innervation of the heart was affected in Tbx1 mutant embryos. In this report, we used an allelic series of Tbx1 mouse mutants, embryo tissue explants and cardiac electrophysiology to characterise, in detail, the function of Tbx1 in vagal innervation of the heart. We found that total nerve branch length was significantly reduced in Tbx1^+/- and Tbx1^neo2/- mutant hearts expressing 50% and 15% levels of Tbx1. We also found that neural crest cells migrated normally to the heart of Tbx1^+/-, but not in Tbx1^neo2 mutant embryos. In addition, we showed that cranial ganglia IX^th and X^th were fused in Tbx1^neo2/- but neuronal differentiation appeared intact. Finally, we used telemetry to monitor heart response to carbachol, a cholinergic receptor agonist, and found that heart rate recovered more quickly in Tbx1^+/- animals versus controls. We speculate that this condition of decreased parasympathetic drive could result in a pro-arrhythmic substrate in some 22q11.2DS patients.

Typical features of Parkinson disease and diagnostic challenges with microdeletion 22q11.2

OBJECTIVE

To delineate the natural history, diagnosis, and treatment response of Parkinson disease (PD) in individuals with 22q11.2 deletion syndrome (22q11.2DS), and to determine if these patients differ from those with idiopathic PD.

METHODS

In this international observational study, we characterized the clinical and neuroimaging features of 45 individuals with 22q11.2DS and PD (mean follow-up 7.5 ± 4.1 years).

RESULTS

22q11.2DS PD had a typical male excess (32 male, 71.1%), presentation and progression of hallmark motor symptoms, reduced striatal dopamine transporter binding with molecular imaging, and initial positive response to levodopa (93.3%). Mean age at motor symptom onset was relatively young (39.5 ± 8.5 years); 71.4% of cases had early-onset PD (<45 years). Despite having a similar age at onset, the diagnosis of PD was delayed in patients with a history of antipsychotic treatment compared with antipsychotic-naive patients (median 5 vs 1 year, p = 0.001). Preexisting psychotic disorders (24.5%) and mood or anxiety disorders (31.1%) were common, as were early dystonia (19.4%) and a history of seizures (33.3%).

CONCLUSIONS

Major clinical characteristics and response to standard treatments appear comparable in 22q11.2DS-associated PD to those in idiopathic PD, although the average age at onset is earlier. Importantly, treatment of preexisting psychotic illness may delay diagnosis of PD in 22q11.DS patients. An index of suspicion and vigilance for complex comorbidity may assist in identifying patients to prioritize for genetic testing.

Congenital heart diseases and cardiovascular abnormalities in 22q11.2 deletion syndrome: From well-established knowledge to new frontiers

Congenital heart diseases (CHDs) and cardiovascular abnormalities are one of the pillars of clinical diagnosis of 22q11.2 deletion syndrome (22q11.2DS) and still represent the main cause of mortality in the affected children. In the past 30 years, much progress has been made in describing the anatomical patterns of CHD, in improving their diagnosis, medical treatment, and surgical procedures for these conditions, as well as in understanding the underlying genetic and developmental mechanisms. However, further studies are still needed to better determine the true prevalence of CHDs in 22q11.2DS, including data from prenatal studies and on the adult population, to further clarify the genetic mechanisms behind the high variability of phenotypic expression of 22q11.2DS, and to fully understand the mechanism responsible for the increased postoperative morbidity and for the premature death of these patients. Moreover, the increased life expectancy of persons with 22q11.2DS allowed the expansion of the adult population that poses new challenges for clinicians such as acquired cardiovascular problems and complexity related to multisystemic comorbidity. In this review, we provide a comprehensive review of the existing literature about 22q11.2DS in order to summarize the knowledge gained in the past years of clinical experience and research, as well as to identify the remaining gaps in comprehension of this syndrome and the possible future research directions.

Elucidating the diagnostic odyssey of 22q11.2 deletion syndrome

Clinical molecular testing has been available for 22q11.2 deletion syndrome (22q11.2DS) for over two decades yet under-recognition and diagnostic delays are common. To characterize the "diagnostic odyssey" in 22q11.2DS we studied 202 well-characterized unrelated adults, none ascertained through an affected relative. We used a regression model to identify clinical and demographic factors associated with length of time to molecular diagnosis. Kaplan-Meier analysis compared time to diagnosis for the molecular testing era (since 1994) and earlier birth cohorts. The results showed that the median time to molecular diagnosis of the 22q11.2 deletion was 4.7 (range 0-20.7) years. Palatal and cardiac anomalies, but not developmental delay/intellectual disability, were associated with a shorter time to molecular diagnosis. Non-European ethnicity was associated with longer time to diagnosis. Inclusion of a cohort from another 22q11.2DS center increased power to observe a significantly earlier diagnosis for patients born in the molecular testing era. Nonetheless, only a minority were diagnosed in the first year of life. On average, patients were seen in seven (range 2-15) different clinical specialty areas prior to molecular diagnosis. The findings indicate that even for those born in the molecular testing era, individuals with 22q11.2DS and their families face a diagnostic odyssey that is often prolonged, particularly in the absence of typical physical congenital features or for those of non-European ancestry. The results support educational efforts to improve clinical recognition and testing, and ultimately newborn screening as a means of maximizing early detection that would provide the best opportunity to optimize outcomes.

The psychosocial impact of 22q11 deletion syndrome on patients and families: A systematic review

The 22q11 deletion syndrome (22q11DS) is one of the most common genomic disorders in humans, affecting around 1:2,000 to 1: 4,000 people. 22q11DS affects multiple body systems and is associated with multiple physical problems. Given the high rate of physical morbidity associated with the 22q11DS, it was hypothesized that it would exert a high psychosocial impact on patients and their relatives. To investigate this, a systematic review of the literature and narrative synthesis was performed. Three major themes emerged. First, the complex and conflicting emotions experienced by family members resulting from the diagnosis. Second, the pervasive educational and health‐care challenges associated with the diagnosis and third that people affect by 22q11DS strived for individualism. The results of this review help to inform clinical management of families with 22q11DS.

Genomic Disorders in Psychiatry-What Does the Clinician Need to Know?

PURPOSE OF REVIEW

The purpose of this review is to summarize the role of genomic disorders in various psychiatric conditions and to highlight important recent advances in the field that are of potential clinical relevance.

RECENT FINDINGS

Genomic disorders are caused by large rare recurrent deletions and duplications at certain chromosomal "hotspots" (e.g., 22q11.2, 16p11.2, 15q11-q13, 1q21.1, 15q13.3) across the genome. Most overlap multiple genes, affect development, and are associated with variable cognitive and other neuropsychiatric expression. Although individually rare, genomic disorders collectively account for a significant minority of intellectual disability, autism spectrum disorder, and schizophrenia. Genome-wide chromosomal microarray analysis is capable of detecting all genomic disorders in a single test, offering the first opportunity for routine clinical genetic testing in psychiatric practice.

Pediatric healthcare costs for patients with 22q11.2 deletion syndrome

BACKGROUND

The 22q11.2 deletion syndrome is a variably expressed disorder that can include cardiac, palate, and other physical abnormalities, immunodeficiency, and hypocalcemia. Because of the extreme variability in phenotype, there has been no available estimate of the total medical expenditure associated with the average case.

METHODS

We have developed a model to estimate the cost from the time of diagnosis to age 20. Costs were based on patients seen at a specialty center but also considered those components of care expected to have been provided by external healthcare facilities. Expense was based on billed medical charges extracted from the electronic medical billing system for all patients with a diagnosis of DiGeorge or velocardiofacial syndrome from 1993-2015. Expenditures included maternal prenatal care directly related to an affected pregnancy, molecular/cytogenetic diagnosis, consultations, surgery, and/or other treatment and management. Most mental health services (except inpatient), therapy related to cognitive, behavioral, speech, pharmacy, and nonmedical costs (special education, vocational, respite, lost earnings) were not included.

RESULTS

Data were available for 642 patients with 50.7% diagnosed prenatally or in the first year of life. The average cost for a patient was $727,178. Costs were highest for patients ascertained prenatally ($2,599,955) or in the first year of life ($1,043,096), those with cardiac abnormalities or referred for cardiac evaluation ($751,535), and patients with low T-cell counts ($1,382,222).

CONCLUSION

This study demonstrates that there are significant medical costs associated with 22q11.2 deletion syndrome.

Delayed diagnosis of 22q11 deletion syndrome due to late onset hypocalcemia in a 11-year-old girl with imperforated anus

Neonatal hypocalcemia and congenital heart defects has been known as the first clinical manifestation of the chromosome 22q11.2 deletion syndrome (22q11DS). However, because of its wide clinical spectrum, diagnosis of 22q11DS can be delayed in children without classic symptoms. We report the case of a girl with the history of imperforate anus but without neonatal hypocalcemia or major cardiac anomaly, who was diagnosed for 22q11DS at the age of 11 after the onset of overt hypocalcemia. She was born uneventfully from phenotypically normal Korean parents. Imperforate anus and partial cleft palate were found at birth, which were surgically repaired thereafter. There was no history of neonatal hypocalcemia, and karyotyping by GTG banding was normal. At the age of 11, hypocalcemia (serum calcium, 5.0 mg/dL) and decreased parathyroid hormone level (10.8 pg/mL) was noted when she visited our Emergency Department for fever and vomiting. The 22q11DS was suspected because of her mild mental retardation and velopharyngeal insufficiency, and a microdeletion on chromosome 22q11.2 was confirmed by fluorescence in situ hybridization. The 22q11DS should be considered in the differential diagnosis of hypocalcemia at any age because of its wide clinical spectrum.

Obesity in adults with 22q11.2 deletion syndrome

PURPOSE

To characterize the prevalence of and contributing factors to adult obesity in the most common recurrent copy-number variation (CNV), 22q11.2 deletion, given that other rare CNVs are known to have obesity phenotypes.

METHODS

In 207 adults with 22q11.2 deletion syndrome (22q11.2DS), we used available height and weight measurements to calculate body mass index (BMI) and recorded associated factors that could play a role in obesity. We used the maximum BMI per subject and logistic regression to test a model predicting obesity class.

RESULTS

The prevalence of obesity (BMI ≥30) in 22q11.2DS (n = 90, 43.5%; at median age of 26.7 years) was significantly greater than for Canadian norms (odds ratio (OR) 2.30, 95% confidence interval (CI) = 1.74-3.02, P < 0.0001), even after excluding individuals with a history of antipsychotic use. The regression model was significant (P < 0.0001). Psychotropic medication use and age, but not sex or presence of intellectual disability, were associated with higher obesity level. Ten (4.8%) individuals were diagnosed with type 2 diabetes at a median age of 39.5 years; the prevalence was higher in those with obesity (P < 0.01).

CONCLUSION

The results suggest that adult obesity is related to the 22q11.2 deletion. The findings expand the potential genetic causes of obesity and have important implications for management of 22q11.2DS.Genet Med 19 2, 204-208.

An Adult Case of Chromosome 22q11.2 Deletion Syndrome Associated with a High-positioned Right Aortic Arch

Chromosome 22q11.2 deletion syndrome (22q11.2 DS) has a very wide phenotypic spectrum that includes dysmorphic features, cardiac anomalies, and hypocalcemia arising from hypoparathyroidism. We herein describe an adult case of 22q11.2 DS with associated hypoparathyroidism and anomalies of the aortic arch. Because the patient had been diagnosed with primary hypoparathyroidism at another hospital, a diagnosis of 22q11.2 DS had been overlooked. A chest X-ray examination revealed widening of the mediastinum caused by a high-positioned right aortic arch, and we subsequently confirmed a diagnosis of 22q11.2 DS using fluorescence in situ hybridization. Because primary hypoparathyroidism is a rare disorder, physicians should be aware of the variable phenotypic features of 22q11.2 DS.

The importance of copy number variation in congenital heart disease

Congenital heart disease (CHD) is the most common class of major malformations in humans. The historical association with large chromosomal abnormalities foreshadowed the role of submicroscopic rare copy number variations (CNVs) as important genetic causes of CHD. Recent studies have provided robust evidence for these structural variants as genome-wide contributors to all forms of CHD, including CHD that appears isolated without extra-cardiac features. Overall, a CNV-related molecular diagnosis can be made in up to one in eight patients with CHD. These include de novo and inherited variants at established (chromosome 22q11.2), emerging (chromosome 1q21.1), and novel loci across the genome. Variable expression of rare CNVs provides support for the notion of a genetic spectrum of CHD that crosses traditional anatomic classification boundaries. Clinical genetic testing using genome-wide technologies (e.g., chromosomal microarray analysis) is increasingly employed in prenatal, paediatric and adult settings. CNV discoveries in CHD have translated to changes to clinical management, prognostication and genetic counselling. The convergence of findings at individual gene and at pathway levels is shedding light on the mechanisms that govern human cardiac morphogenesis. These clinical and research advances are helping to inform whole-genome sequencing, the next logical step in delineating the genetic architecture of CHD.

Cardiac sympathetic activity in 22q11.2 deletion syndrome

AIM

22q11.2 deletion syndrome (22q11.2DS) affects catechol-O-methyl-transferase (COMT), which involves the degradation of norepinephrine (NE). Clinically, adults with 22q11.2DS are at increased risk for sudden unexpected death. Although the causes are likely multifactorial, increased cardiac sympathetic activity with subsequent fatal arrhythmia, due to increased levels of NE, should be considered as a possible mechanism predisposing to this premature death. The purpose of this study was to determine whether cardiac sympathetic activity is increased in 22q11.2DS, both at baseline and following an acute NE depletion with alpha-methyl-para-tyrosine (AMPT).

METHODS

Five adults with 22q11.2DS and five age- and sex-matched healthy controls underwent 2 sessions with either AMPT or placebo administration before (123)I-mIBG scintigraphy. Heart-to-mediastinum ratios (H/M) were determined from the images 15min (early) and 4h (late) after administration of (123)I-mIBG and the washout (WO) was calculated as an indicator of adrenergic drive.

RESULTS

At baseline there were no significant differences in both early and late H/M between 22q11.2DS and controls. However, there was a significant difference in WO between 22q11.2DS and controls (-4.92±2.8 and -10.44±7.2, respectively; p=0.027), but a "negative WO" does not support an increased sympathetic drive. In addition there was a trend towards a higher late H/M after AMPT administration compared to baseline which was more pronounced in 22q11.2DS.

CONCLUSION

This study for the first time suggests normal cardiac sympathetic activity in adults with 22q11.2DS assessed by (123)I-mIBG scintigraphy. Although there is a small difference in adrenergic drive compared to healthy subjects, this most likely does not explain the increased unexpected death rate in the 22q11.2 DS population.

Deletions at 22q11.2 in idiopathic Parkinson's disease: a combined analysis of genome-wide association data

BACKGROUND

Parkinson's disease has been reported in a small number of patients with chromosome 22q11.2 deletion syndrome. In this study, we screened a series of large, independent Parkinson's disease case-control studies for deletions at 22q11.2.

METHODS

We used data on deletions spanning the 22q11.2 locus from four independent case-control Parkinson's disease studies (UK Wellcome Trust Case Control Consortium 2, Dutch Parkinson's Disease Genetics Consortium, US National Institute on Aging, and International Parkinson's Disease Genomics Consortium studies), which were independent of the original reports of chromosome 22q11.2 deletion syndrome. We did case-control association analysis to compare the proportion of 22q11.2 deletions found, using the Fisher's exact test for the independent case-control studies and the Mantel-Haenszel test for the meta-analyses. We retrieved clinical details of patients with Parkinson's disease who had 22q11.2 deletions from the medical records of these patients.

FINDINGS

We included array-based copy number variation data from 9387 patients with Parkinson's disease and 13 863 controls. Eight patients with Parkinson's disease and none of the controls had 22q11.2 deletions (p=0·00082). In the 8451 patients for whom age at onset data were available, deletions at 22q11.2 were associated with Parkinson's disease age at onset (Mann-Whitney U test p=0·001). Age at onset of Parkinson's disease was lower in patients carrying a 22q11.2 deletion (median 37 years, 95% CI 32·0-55·5; mean 42·1 years [SD 11·9]) than in those who did not carry a deletion (median 61 years, 95% CI 60·5-61·0; mean 60·3 years [SD 12·8]). A 22q11.2 deletion was present in more patients with early-onset (p<0·0001) and late-onset Parkinson's disease (p=0·016) than in controls, and in more patients with early-onset than late-onset Parkinson's disease (p=0·005).

INTERPRETATION

Clinicians should be alert to the possibility of 22q11.2 deletions in patients with Parkinson's disease who have early presentation or features associated with the chromosome 22q11.2 deletion syndrome, or both.

FUNDING

UK Medical Research Council, UK Wellcome Trust, Parkinson's UK, Patrick Berthoud Trust, National Institutes of Health, "Investissements d'Avenir" ANR-10-IAIHU-06, Dutch Parkinson Foundation (Parkinson Vereniging), Neuroscience Campus Amsterdam, National Institute for Health Research, National Institute on Aging, National Institutes of Health.

22q11.2 deletion syndrome

22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion disorder, estimated to result mainly from de novo non-homologous meiotic recombination events occurring in approximately 1 in every 1,000 fetuses. The first description in the English language of the constellation of findings now known to be due to this chromosomal difference was made in the 1960s in children with DiGeorge syndrome, who presented with the clinical triad of immunodeficiency, hypoparathyroidism and congenital heart disease. The syndrome is now known to have a heterogeneous presentation that includes multiple additional congenital anomalies and later-onset conditions, such as palatal, gastrointestinal and renal abnormalities, autoimmune disease, variable cognitive delays, behavioural phenotypes and psychiatric illness - all far extending the original description of DiGeorge syndrome. Management requires a multidisciplinary approach involving paediatrics, general medicine, surgery, psychiatry, psychology, interventional therapies (physical, occupational, speech, language and behavioural) and genetic counselling. Although common, lack of recognition of the condition and/or lack of familiarity with genetic testing methods, together with the wide variability of clinical presentation, delays diagnosis. Early diagnosis, preferably prenatally or neonatally, could improve outcomes, thus stressing the importance of universal screening. Equally important, 22q11.2DS has become a model for understanding rare and frequent congenital anomalies, medical conditions, psychiatric and developmental disorders, and may provide a platform to better understand these disorders while affording opportunities for translational strategies across the lifespan for both patients with 22q11.2DS and those with these associated features in the general population.

Undiagnosed DiGeorge syndrome presenting in middle age with an aortic root aneurysm and chronic dissection

DiGeorge syndrome is the second commonest cause of congenital heart disease after trisomy 21. This case illustrates an undiagnosed case of DiGeorge syndrome for a patient who had a ventricular septal defect repair in childhood. He survived well into his adult years, and was only diagnosed post mortem after an unsuccessful repair of an aortic root aneurysm. The case serves as an example supporting genetic screening of children with congenital heart disease, and lifelong cardiology follow-up for patients with a confirmed genotype.

Practical guidelines for managing adults with 22q11.2 deletion syndrome

22q11.2 Deletion syndrome (22q11.2DS) is the most common microdeletion syndrome in humans, estimated to affect up to 1 in 2,000 live births. Major features of this multisystem condition include congenital anomalies, developmental delay, and an array of early- and later-onset medical and psychiatric disorders. Advances in pediatric care ensure a growing population of adults with 22q11.2DS. Informed by an international panel of multidisciplinary experts and a comprehensive review of the existing literature concerning adults, we present the first set of guidelines focused on managing the neuropsychiatric, endocrine, cardiovascular, reproductive, psychosocial, genetic counseling, and other issues that are the focus of attention in adults with 22q11.2DS. We propose practical strategies for the recognition, evaluation, surveillance, and management of the associated morbidities.Genet Med 17 8, 599-609.

Comparative mapping of the 22q11.2 deletion region and the potential of simple model organisms

Background

22q11.2 deletion syndrome (22q11.2DS) is the most common micro-deletion syndrome. The associated 22q11.2 deletion conveys the strongest known molecular risk for schizophrenia. Neurodevelopmental phenotypes, including intellectual disability, are also prominent though variable in severity. Other developmental features include congenital cardiac and craniofacial anomalies. Whereas existing mouse models have been helpful in determining the role of some genes overlapped by the hemizygous 22q11.2 deletion in phenotypic expression, much remains unknown. Simple model organisms remain largely unexploited in exploring these genotype-phenotype relationships.

Methods

We first developed a comprehensive map of the human 22q11.2 deletion region, delineating gene content, and brain expression. To identify putative orthologs, standard methods were used to interrogate the proteomes of the zebrafish (D. rerio), fruit fly (D. melanogaster), and worm (C. elegans), in addition to the mouse. Spatial locations of conserved homologues were mapped to examine syntenic relationships. We systematically cataloged available knockout and knockdown models of all conserved genes across these organisms, including a comprehensive review of associated phenotypes.

Results

There are 90 genes overlapped by the typical 2.5 Mb deletion 22q11.2 region. Of the 46 protein-coding genes, 41 (89.1 %) have documented expression in the human brain. Identified homologues in the zebrafish (n = 37, 80.4 %) were comparable to those in the mouse (n = 40, 86.9 %) and included some conserved gene cluster structures. There were 22 (47.8 %) putative homologues in the fruit fly and 17 (37.0 %) in the worm involving multiple chromosomes. Individual gene knockdown mutants were available for the simple model organisms, but not for mouse. Although phenotypic data were relatively limited for knockout and knockdown models of the 17 genes conserved across all species, there was some evidence for roles in neurodevelopmental phenotypes, including four of the six mitochondrial genes in the 22q11.2 deletion region.

Conclusions

Simple model organisms represent a powerful but underutilized means of investigating the molecular mechanisms underlying the elevated risk for neurodevelopmental disorders in 22q11.2DS. This comparative multi-species study provides novel resources and support for the potential utility of non-mouse models in expression studies and high-throughput drug screening. The approach has implications for other recurrent copy number variations associated with neurodevelopmental phenotypes.

Electronic supplementary material

The online version of this article (doi:10.1186/s11689-015-9113-x) contains supplementary material, which is available to authorized users.

Developmental trajectories in 22q11.2 deletion

Chromosome 22q11.2 deletion syndrome (22q11.2DS), a neurogenetic condition, is the most common microdeletion syndrome affecting 1 in 2,000-4,000 live births and involving haploinsufficiency of ∼50 genes resulting in a multisystem disorder. Phenotypic expression is highly variable and ranges from severe life-threatening conditions to only a few associated features. Most common medical problems include: congenital heart disease, in particular conotruncal anomalies; palatal abnormalities, most frequently velopharyngeal incompetence (VPI); immunodeficiency; hypocalcemia due to hypoparathyroidism; genitourinary anomalies; severe feeding/gastrointestinal differences; and subtle dysmorphic facial features. The neurocognitive profile is also highly variable, both between individuals and during the course of development. From infancy onward, motor delays (often with hypotonia) and speech/language deficits are commonly observed. During the preschool and primary school ages, learning difficulties are very common. The majority of patients with 22q11.2DS have an intellectual level that falls in the borderline range (IQ 70-84), and about one-third have mild to moderate intellectual disability. More severe levels of intellectual disability are uncommon in children and adolescents but are more frequent in adults. Individuals with 22q11.2DS are at an increased risk for developing several psychiatric disorders including attention deficit with hyperactivity disorder (ADHD), autism spectrum disorder (ASD), anxiety and mood disorders, and psychotic disorders and schizophrenia. In this review, we will focus on the developmental phenotypic transitions regarding cognitive development in 22q11.2DS from early preschool to adulthood, and on the changing behavioral/psychiatric phenotype across age, on a background of frequently complex medical conditions.

Reproductive Health Issues for Adults with a Common Genomic Disorder: 22q11.2 Deletion Syndrome

22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion syndrome in humans. Survival to reproductive age and beyond is now the norm. Several manifestations of this syndrome, such as congenital cardiac disease and neuropsychiatric disorders, may increase risk for adverse pregnancy outcomes in the general population. However, there are limited data on reproductive health in 22q11.2DS. We performed a retrospective chart review for 158 adults with 22q11.2DS (75 male, 83 female; mean age 34.3 years) and extracted key variables relevant to pregnancy and reproductive health. We present four illustrative cases as brief vignettes. There were 25 adults (21 > age 35 years; 21 female) with a history of one or more pregnancies. Outcomes for women with 22q11.2DS, compared with expectations for the general population, showed a significantly elevated prevalence of small for gestational age liveborn offspring (p < 0.001), associated mainly with infants with 22q11.2DS. Stillbirths also showed elevated prevalence (p < 0.05). Not all observed adverse events appeared to be attributable to transmission of the 22q11.2 deletion. Recurring issues relevant to reproductive health in 22q11.2DS included the potential impact of maternal morbidities, inadequate social support, unsafe sexual practices, and delayed diagnosis of 22q11.2DS and/or lack of genetic counseling. These preliminary results emphasize the importance of early diagnosis and long term follow-up that could help facilitate genetic counseling for men and women with 22q11.2DS. We propose initial recommendations for pre-conception management, educational strategies, prenatal planning, and preparation for possible high-risk pregnancy and/or delivery.

Case fatality rate and associated factors in patients with 22q11 microdeletion syndrome: a retrospective cohort study

OBJECTIVE

Chromosome 22q11.2 deletion is the most commonly occurring known microdeletion syndrome. Deaths related to the syndrome have been reported, but the magnitude of death has not been quantified. This study evaluated the deletion's impact on survival and its clinical manifestations in a large cohort of Chilean patients.

DESIGN

Demographic and clinical data of individuals with 22q11 deletions diagnosed between 1998 and 2013 were collected from medical records and death certificates. Case fatality rate was calculated and compared with national vital statistics. OR with 95% CI analysis was used to assess the association between clinical manifestations and death.

SETTING

Genetic services in tertiary care centres in Chile, following patients with 22q11.2 deletion.

OUTCOMES

Fatality rate and associated factors.

RESULTS

59 of 419 patients (14.1%) died during the study period at a median of 3.4 months (range 0 to 32 years of age). Factors associated with death included congenital heart disease (OR 5.27; 95% CI 2.06 to 13.99; p<0.0001), hypocalcaemia (OR 4.27; 95% CI 1.67 to 11.15; p<0.002) and airway malacia (OR 13.37; 95% CI 1.19 to 110.51; p<0.002). Patients with deletions and defects such as tetralogy of Fallot with or without pulmonary atraesia, truncus arteriosus or ventricular septal defect, had a 2.6-fold to 4.6-fold higher death rate compared with nationwide reports for the same types of defects.

CONCLUSIONS

In this cohort, we observed a death rate of 14.1%, implying that one in seven patients with 22q11 deletion died during the study period. Significant associations with cardiac defects, hypocalcaemia and airway malacia were observed. Furthermore, the death risk in patients with 22q11 deletion and cardiac defects exceeded the global figures observed in Chile for infants with structurally similar but apparently isolated anomalies. These observations indicate a need to identify patients who may require specific perioperative management to improve survival.

Prevalence of hypocalcaemia and its associated features in 22q11·2 deletion syndrome

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a relatively common yet under-recognized genetic syndrome that may present with endocrine features. We aimed to address the factors that contribute to the high prevalence of hypocalcaemia.

METHODS

We investigated hypocalcaemia in a well-characterized sample of 138 adults with 22q11.2DS (65 m, 73 F; mean age 34.2, SD 11.8, years) using laboratory studies and lifelong medical records. Logistic regression modelling was used to identify features associated with lifetime prevalence of hypocalcaemia.

RESULTS

Of the total sample, 111 (80.4%) had a lifetime history of hypocalcaemia. Eleven (84.6%) of 13 subjects with neonatal hypocalcaemia had documented recurrence of hypocalcaemia. Lifetime history of hypocalcaemia was associated with lifetime prevalence of hypoparathyroidism (P < 0.0001) and hypothyroidism (P = 0.04), as statistically independent factors. Hypomagnesaemia was associated with concurrent hypocalcaemic measurements, especially in the presence of concurrent hypoparathyroidism (P = 0.02).

CONCLUSIONS

The results suggest that, in addition to the major effect of hypoparathyroidism, hypothyroidism may play a role in hypocalcaemia in 22q11.2DS and that there is a high recurrence rate of neonatal hypocalcaemia. Hypomagnesaemia may contribute to hypocalcaemia by further suppressing parathyroid hormone (PTH). Although further studies are needed, the findings support regular lifelong follow-up of calcium, magnesium, PTH and TSH levels in patients with 22q11.2DS. At any age, hypocalcaemia with hypoparathyroidism and/or hypothyroidism may suggest a diagnosis of 22q11.2DS.

Under-recognition of 22q11.2 deletion in adult Chinese patients with conotruncal anomalies: implications in transitional care

22q11.2 deletion syndrome (22q11.2DS) is a multi-systemic disorder with high phenotypic variability. Under-diagnosis in adults is common and recognition of facial dysmorphic features can be affected by age and ethnicity. This study aims to determine the prevalence of undiagnosed 22q11.2DS in adult Chinese patients with conotruncal anomalies and to delineate their facial dysmorphisms and extra-cardiac manifestations. We recruited consecutively 156 patients with conotruncal anomalies in an adult congenital heart disease (CHD) clinic in Hong Kong and screened for 22q11.2DS using fluorescence-PCR and fluorescence in-situ hybridization. Assessment for dysmorphic features was performed by a cardiologist at initial screening and then by a clinical geneticist upon result disclosure. Clinical photographs were taken and childhood photographs collected. Eighteen patients (11.5%) were diagnosed with 22q11.2DS, translating into 1 previously unrecognized diagnosis of 22q11.2DS in every 10 adult patients with conotruncal anomalies. While dysmorphic features were detected by our clinical geneticist in all patients, only two-thirds were considered dysmorphic by our cardiologist upon first assessment. Evolution of facial dysmorphic features was noted with age. Extra-cardiac manifestations included velopharyngeal incompetence or cleft palate (44%), hypocalcemia (39%), neurodevelopmental anomalies (33%), thrombocytopenia (28%), psychiatric disorders (17%), epilepsy (17%) and hearing loss (17%). We conclude that under-diagnosis of 22q11.2DS in Chinese adults with conotruncal defects is common and facial dysmorphic features may not be reliably recognized in the setting of adult CHD clinic, referral for genetic evaluation and molecular testing for 22q11.2DS should be offered to patients with conotruncal defects.

Presenting symptoms in adults with the 22q11 deletion syndrome

A definitive molecular diagnosis of 22q11 Deletion Syndrome (22q11DS) even if occurring later in life, has important genetic, medical and emotional impact on the patients and their families. The aim of this study is to describe presenting symptoms and age at diagnosis in an adult 22q11DS population. A retrospective study was performed on 65 individuals diagnosed with 22q11DS at adult age. Data were collected on adults referred to the genetic clinic or actively recruited through systematic diagnostic examination in both institutions and a psychiatric unit for intellectually disabled. Presenting symptoms were categorized into seven groups: familial occurrence, intellectual disability, cardiac anomalies, palatal anomalies, facial dysmorphic features, psychiatric problems and 'other' (comprising all other features associated with 22q11DS). Age at diagnosis was defined as the age at which the 22q11.2 deletion was detected by fluorescence in situ hybridization or comparative genomic hybridization. Ascertainment subgroups were different in presenting symptoms and age at diagnosis. Adults were referred to the genetic clinic mainly because of familial occurrence, cardiac defects and psychiatric disorders whereas adults diagnosed in institutions for intellectually disabled presented mainly with moderate to severe intellectual disability and psychotic disorders. Adults diagnosed at the psychiatric unit for intellectually disabled had a variety of psychiatric disorders but none of them had additional physical features. This emphasizes the need to stay alert for presenting symptoms such as conotruncal heart defects or moderate to severe intellectual disability in combination with a history of psychiatric disorders, even in the absence of obvious physical features.

Perceived burden and neuropsychiatric morbidities in adults with 22q11.2 deletion syndrome

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a common genetic subtype of intellectual disability (ID) remarkable for its constellation of congenital, developmental and later-onset features. Survival to adulthood is now the norm, and serious psychiatric illness is common in adults. However, little is known about the experiences and perceived needs of individuals with 22q11.2DS and their caregivers at time of transition from paediatric to adult models of care and beyond.

METHOD

We administered a mail survey to 84 caregivers of adults with 22q11.2DS and 34 adult patients themselves, inquiring about medical and social services, perceived burden and major challenges in adulthood in 22q11.2DS. Standard quantitative and qualitative methods were used to analyse the responses.

RESULTS

Fifty-three (63.1%) caregivers and 20 (58.8%) adults with 22q11.2DS completed the survey. Perceived burden was high, with psychiatric illness and/or behavioural issues considered the most challenging aspects of adulthood in 22q11.2DS by the majority of caregivers (70.0%) and many patients themselves (42.9%). Irrespective of the extent of ID and the presence or absence of other major features, caregivers expressed dissatisfaction with medical and social services for adults, including at time of transition from paediatric care.

CONCLUSIONS

To our knowledge, this is the first study to examine the subjective experiences of adults with 22q11.2DS and their caregivers and to identify their perceived needs for services. Better awareness of 22q11.2DS and its later-onset manifestations, early diagnosis and treatment of psychiatric illness, additional support at time of transition and dedicated clinics for adults with 22q11.2DS may help to improve patient outcomes and reduce caregiver burden.

Towards a safety net for management of 22q11.2 deletion syndrome: guidelines for our times

The commonest autosomal deletion, 22q11.2 deletion syndrome (22q11DS) is a multisystem disorder varying greatly in severity and age of identification between affected individuals. Holistic care is best served by a multidisciplinary team, with an anticipatory approach. Priorities tend to change with age, from feeding difficulties, infections and surgery of congenital abnormalities particularly of the heart and velopharynx in infancy and early childhood to longer-term communication, learning, behavioural and mental health difficulties best served by evaluation at intervals to consider and initiate management. Regular monitoring of growth, endocrine status, haematological and immune function to enable early intervention helps in maintaining health.

CONCLUSION

Guidelines to best practice management of 22q11DS based on a literature review and consensus have been developed by a national group of professionals with consideration of the limitations of available medical and educational resources.

Association between early-onset Parkinson disease and 22q11.2 deletion syndrome: identification of a novel genetic form of Parkinson disease and its clinical implications

IMPORTANCE

Clinical case reports of parkinsonism co-occurring with hemizygous 22q11.2 deletions and the associated multisystem syndrome, 22q11.2 deletion syndrome (22q11.2DS), suggest that 22q11.2 deletions may lead to increased risk of early-onset Parkinson disease (PD). The frequency of PD and its neuropathological presentation remain unknown in this common genetic condition.

OBJECTIVE

To evaluate a possible association between 22q11.2 deletions and PD.

DESIGN, SETTING, AND PARTICIPANTS

An observational study of the occurrence of PD in the world's largest cohort of well-characterized adults with a molecularly confirmed diagnosis of 22q11.2DS (n = 159 [6 with postmortem tissue]; age range, 18.1-68.6 years) was conducted in Toronto, Ontario, Canada. Rare postmortem brain tissue from individuals with 22q11.2DS and a clinical history of PD was investigated for neurodegenerative changes and compared with that from individuals with no history of a movement disorder.

MAIN OUTCOMES AND MEASURES

A clinical diagnosis of PD made by a neurologist and neuropathological features of PD. RESULTS Adults with 22q11.2DS had a significantly elevated occurrence of PD compared with standard population estimates (standardized morbidity ratio = 69.7; 95% CI, 19.0-178.5). All cases showed early onset and typical PD symptom pattern, treatment response, and course. All were negative for family history of PD and known pathogenic PD-related mutations. The common use of antipsychotics in patients with 22q11.2DS to manage associated psychiatric symptoms delayed diagnosis of PD by up to 10 years. Postmortem brain tissue revealed classic loss of midbrain dopaminergic neurons in all 3 postmortem 22q11.2DS-PD cases. Typical α-synuclein-positive Lewy bodies were present in the expected distribution in 2 cases but absent in another.

CONCLUSIONS AND RELEVANCE

These findings suggest that 22q11.2 deletions represent a novel genetic risk factor for early-onset PD with variable neuropathological presentation reminiscent of LRRK2-associated PD neuropathology. Individuals with early-onset PD and classic features of 22q11.2DS should be considered for genetic testing, and those with a known 22q11.2 deletion should be monitored for the development of parkinsonian symptoms. Molecular studies of the implicated genes, including DGCR8, may help shed light on the underlying pathophysiology of PD in 22q11.2DS and idiopathic PD.