Spectrum of clinical variability in familial deletion 22q11.2: from full manifestation to extremely mild clinical anomalies

Musculoskeletal phenotypes in 3q29 deletion syndrome

3q29 deletion syndrome (3q29del) is a rare genomic disorder caused by a 1.6 Mb deletion (hg19, chr3:195725000-197350000). 3q29del is associated with neurodevelopmental and psychiatric phenotypes, including an astonishing >40-fold increased risk for schizophrenia, but medical phenotypes are less well-described. We used the online 3q29 registry of 206 individuals (3q29deletion.org) to recruit 57 individuals with 3q29del (56.14% male) and requested information about musculoskeletal phenotypes with a custom questionnaire. 85.96% of participants with 3q29del reported at least one musculoskeletal phenotype. Congenital anomalies were most common (70.18%), with pes planus (40.35%), pectus excavatum (22.81%), and pectus carinatum (5.26%) significantly elevated relative to the pediatric general population. 49.12% of participants reported fatigue after 30 min or less of activity. Bone fractures (8.77%) were significantly elevated relative to the pediatric general population. Participants commonly report receiving medical care for musculoskeletal complaints (71.93%), indicating that these phenotypes impact quality of life for individuals with 3q29del. This is the most comprehensive description of musculoskeletal phenotypes in 3q29del to date, suggests ideas for clinical evaluation, and expands our understanding of the phenotypic spectrum of this syndrome.

Chromosome 22q11.2 Deletion Syndrome: A Comprehensive Review of Molecular Genetics in the Context of Multidisciplinary Clinical Approach

The 22q11.2 deletion syndrome is a multisystemic disorder characterized by a marked variability of phenotypic features, making the diagnosis challenging for clinicians. The wide spectrum of clinical manifestations includes congenital heart defects-most frequently conotruncal cardiac anomalies-thymic hypoplasia and predominating cellular immune deficiency, laryngeal developmental defects, midline anomalies with cleft palate and velar insufficiency, structural airway defects, facial dysmorphism, parathyroid and thyroid gland hormonal dysfunctions, speech delay, developmental delay, and neurocognitive and psychiatric disorders. Significant progress has been made in understanding the complex molecular genetic etiology of 22q11.2 deletion syndrome underpinning the heterogeneity of clinical manifestations. The deletion is caused by chromosomal rearrangements in meiosis and is mediated by non-allelic homologous recombination events between low copy repeats or segmental duplications in the 22q11.2 region. A range of genetic modifiers and environmental factors, as well as the impact of hemizygosity on the remaining allele, contribute to the intricate genotype-phenotype relationships. This comprehensive review has been aimed at highlighting the molecular genetic background of 22q11.2 deletion syndrome in correlation with a clinical multidisciplinary approach.

Musculoskeletal phenotypes in 3q29 deletion syndrome

3q29 deletion syndrome (3q29del) is a rare genomic disorder caused by a 1.6 Mb deletion (hg19, chr3:195725000â€"197350000). 3q29del is associated with neurodevelopmental and psychiatric phenotypes, including an astonishing >40-fold increased risk for schizophrenia, but medical phenotypes are less well-described. We used the online 3q29 registry ( 3q29deletion.org ) to recruit 57 individuals with 3q29del (56.14% male) and requested information about musculoskeletal phenotypes with a custom questionnaire. 85.96% of participants with 3q29del reported at least one musculoskeletal phenotype. Congenital anomalies were most common (70.18%), with pes planus (40.35%), pectus excavatum (22.81%), and pectus carinatum (5.26%) significantly elevated relative to the pediatric general population. 49.12% of participants reported fatigue after 30 minutes or less of activity. Bone fractures (8.77%) were significantly elevated relative to the pediatric general population, suggesting 3q29del impacts bone strength. Participants commonly report receiving medical care for musculoskeletal complaints (71.93%), indicating that these phenotypes impact quality of life for individuals with 3q29del. This is the most comprehensive description of musculoskeletal phenotypes in 3q29del to date, suggests ideas for clinical evaluation, and expands our understanding of the phenotypic spectrum of this syndrome.

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.

Genetics of congenital heart disease: a narrative review of recent advances and clinical implications

Congenital heart disease (CHD) is the most common human birth defect and remains a leading cause of mortality in childhood. Although advances in clinical management have improved the survival of children with CHD, adult survivors commonly experience cardiac and non-cardiac comorbidities, which affect quality of life and prognosis. Therefore, the elucidation of genetic etiologies of CHD not only has important clinical implications for genetic counseling of patients and families but may also impact clinical outcomes by identifying at-risk patients. Recent advancements in genetic technologies, including massively parallel sequencing, have allowed for the discovery of new genetic etiologies for CHD. Although variant prioritization and interpretation of pathogenicity remain challenges in the field of CHD genomics, advances in single-cell genomics and functional genomics using cellular and animal models of CHD have the potential to provide novel insights into the underlying mechanisms of CHD and its associated morbidities. In this review, we provide an updated summary of the established genetic contributors to CHD and discuss recent advances in our understanding of the genetic architecture of CHD along with current challenges with the interpretation of genetic variation. Furthermore, we highlight the clinical implications of genetic findings to predict and potentially improve clinical outcomes in patients with CHD.

Care of Children with DiGeorge Before and After Cultured Thymus Tissue Implantation

BACKGROUND

Children with complete DiGeorge anomaly (cDGA) have congenital athymia plus a myriad of other challenging clinical conditions. The term cDGA encompasses children with congenital athymia secondary to 22q11.2DS, CHARGE syndrome (coloboma, heart defects, choanal atresia, growth or mental retardation, genital abnormalities, and ear abnormalities and/or deafness), and other genetic abnormalities. Some children have no known genetic defects. Since 1993, more than 100 children with congenital athymia have been treated with cultured thymus tissue implantation (CTTI). Naïve T cells develop approximately 6 to 12 months after CTTI. Most of the children had significant comorbidities such as heart disease, hypoparathyroidism, and infections requiring complex clinical care post cultured thymus tissue implantation (CTTI).

OBJECTIVE

The purpose of this guidance is to assist multidisciplinary teams in caring for children with cDGA both before and after CTTI.

METHODS

Thirty-one specialists, in addition to the authors, were asked to share their experience in caring for children with cDGA at Duke University Health System, before and after CTTI. These specialists included physicians, nurses, dentists, therapists, and dieticians.

RESULTS

The goal of a multidisciplinary approach is to have children in the best possible condition for receiving CTTI and provide optimal care post CTTI through development of naïve T cells and beyond. The CTT (cultured thymus tissue) must be protected from high doses of steroids which can damage CTT. Organs must be protected from adverse effects of immunosuppression.

CONCLUSION

Creating a multidisciplinary team and a detailed plan of care for children with cDGA is important for optimal outcomes.

Prenatal sonographic and cytogenetic/molecular findings of 22q11.2 microdeletion syndrome in 48 confirmed cases in a single tertiary center

PURPOSE

We aimed to present the fetal ultrasound, cytogenetic/molecular testing and postmortem or postnatal clinical findings of cases with 22q11.2DS diagnosed prenatally.

MATERIALS AND METHODS

A retrospective medical record review of 48 prenatal cases diagnosed with 22q11.2DS were evaluated in our institution. Detailed ultrasound examination was performed on all fetuses. Postmortem and postnatal examinations were evaluated. The microdeletions were detected by karyotyping or microarray, then confirmed by FISH. Descriptive statistical analysis was performed.

RESULTS

Demographic data of 48 prenatal cases including 46 singletons and 1 dichorionic diamniotic twin pregnancy were evaluated. The most common extracardiac anomaly was skeletal system anomalies (25%), in which PEV was the most frequent one (20.8%). Polyhydramnios rate was detected as 31%, in 6.6% as an isolated finding. Microdeletion has been detected by karyotyping in 13 cases (13/47, 27.7%) (including 2 unbalanced translocations), by FISH in 28 cases (28/48, 58.3%), by microarray/a-CGH testing in 7 cases. Microarray analysis showed that in one case with unbalanced translocation had two consecutive deletions; one was proximal and other one distal to critical region and not encompassing TBX1 gene but CRKL and LZTR1 genes.

CONCLUSION

The current study demonstrates the whole spectrum of atypical phenotypic and genotypic variations of 22q11.2DS in the largest prenatal case series reported to date. Therefore, differential diagnosis should be considered not solely in CHD, but also in the presence of isolated clubfeet and polyhydramnios. Establishing the diagnosis in the prenatal period may allow a postnatal multidisciplinary approach, as well as affect the actual prevalence of the disease.

Social cognition in 22q11.2 deletion syndrome and idiopathic developmental neuropsychiatric disorders

BACKGROUND

22q11.2 deletion syndrome (22q11DS) is a common recurrent neurogenetic condition associated with elevated risk for developmental neuropsychiatric disorders and intellectual disability. Children and adults with 22q11DS often exhibit marked social impairment as well as neurocognitive deficits, and have elevated rates of both autism spectrum disorder (ASD) and psychosis. However, the relationship between the basic processes of social cognition and cognitive ability has not been well studied in 22q11DS. Here, we examined differences in social cognition in 22q11DS, relative to multiple groups of idiopathic neuropsychiatric disorders, and typically developing healthy controls (HC). Additionally, we examined differences in intellectual functioning and its relationship to social cognitive abilities. Finally, we examined the relationship between social cognitive abilities and real-world social behavior.

METHODS

We examined social cognition and intellectual functioning in 273 participants (mean age = 17.74 ± 5.18% female = 44.3%): 50 with 22q11DS, 49 youth with first episode psychosis (FEP), 48 at clinical high-risk (CHR) for psychosis, 24 participants with ASD, and 102 HC. Social cognition was assessed using The Awareness of Social Inference Test (TASIT), while reciprocal social behavior was assessed via parent/caregiver ratings on the Social Responsiveness Scale (SRS). Participants were also administered the Wechsler Abbreviated Scale of Intelligence, 2nd edition (WASI-II) to assess intellectual functioning.

RESULTS

The 22q11DS group exhibited significantly lower social cognitive abilities compared to CHR, FEP, and HC groups after controlling for intellectual functioning, but not in comparison to the ASD group. Significant positive correlations were found between social cognition, as measured by the TASIT and IQ across groups. In contrast, no significant relationships were found between TASIT and real-world social behavior (SRS) for any group.

CONCLUSIONS

Our findings indicate social cognitive deficits are more prominent in 22q11DS than idiopathic neuropsychiatric conditions across the age range, even after adjusting for global intellectual function. These results contribute to our understanding of the intellectual and social vulnerabilities of 22q11DS in comparison to idiopathic neuropsychiatric disorders. Our findings of robust associations between intellectual ability and social cognition emphasizes the importance of accounting for neurocognitive deficits in social skills interventions and tailoring these existing treatment models for 22q11DS and other populations with intellectual impairment.

Contribution of Mitochondrial DNA Heteroplasmy to the Congenital Cardiac and Palatal Phenotypic Variability in Maternally Transmitted 22q11.2 Deletion Syndrome

Congenital heart disease (CHD) and palatal anomalies (PA), are among the most common characteristics of 22q11.2 deletion syndrome (22q11.2DS), but they show incomplete penetrance, suggesting the presence of additional factors. The 22q11.2 deleted region contains nuclear encoded mitochondrial genes, and since mitochondrial function is critical during development, we hypothesized that changes in the mitochondrial DNA (mtDNA) could be involved in the intrafamilial variability of CHD and PA in cases of maternally inherited 22q11.2DS. To investigate this, we studied the transmission of heteroplasmic mtDNA alleles in seventeen phenotypically concordant and discordant mother-offspring 22q11.2DS pairs. We sequenced their mtDNA and identified 26 heteroplasmic variants at >1% frequency, representing 18 transmissions. The median allele frequency change between a mother and her child was twice as much, with a wider distribution range, in PA discordant pairs, p-value = 0.039 (permutation test, 11 concordant vs. 7 discordant variants), but not in CHD discordant pairs, p-value = 0.441 (9 vs. 9). Only the variant m.9507T>C was considered to be pathogenic, but it was unrelated to the structural phenotypes. Our study is novel, yet our results are not consistent with mtDNA variation contributing to PA or CHD in 22q11.2DS. Larger cohorts and additional factors should be considered moving forward.

Epidemiological Research of Microtia Combined With Congenital Heart Disease

Congenital heart disease (CHD) is one of the most common combined malformations of microtia. There is currently no specific study that investigates the relationship between microtia and CHD.

METHODS

This study collected microtia inpatients admitted from May 1, 2015 to July 31, 2016. The diagnosis of CHD was based on patient's symptoms, past history, and echocardiography. Pearson χ test was used to analyze the correlation between CHD and microtia.

RESULTS

A total of 30 cases (3.35%) were documented with CHD, including atrial septal defect (12/40.00%), ventricular septal defect (7/23.30%), patent ductus arteriosus (2/6.70%), complex congenital heart disease (3/10.00%), combined CHD (2/6.70%) and other malformations (4/13.30%). Analysis showed no statistically significant relation between CHD and the side of affected ear or gender.

CONCLUSIONS

The occurrence of CHD in microtia patients was higher than that in the general population. The relationship between them was explored mainly from the etiological perspective. Microtia and CHD were often combined in syndromes such as Goldenhar syndrome, 22q11 deletion syndrome, and CHARGE syndrome. Absence of genes or abnormal embryo development associated with these syndromes leads to the occurrence of both.

Genetic Basis of Human Congenital Heart Disease

Congenital heart disease (CHD) is the most common major congenital anomaly with an incidence of ∼1% of live births and is a significant cause of birth defect-related mortality. The genetic mechanisms underlying the development of CHD are complex and remain incompletely understood. Known genetic causes include all classes of genetic variation including chromosomal aneuploidies, copy number variants, and rare and common single-nucleotide variants, which can be either de novo or inherited. Among patients with CHD, ∼8%-12% have a chromosomal abnormality or aneuploidy, between 3% and 25% have a copy number variation, and 3%-5% have a single-gene defect in an established CHD gene with higher likelihood of identifying a genetic cause in patients with nonisolated CHD. These genetic variants disrupt or alter genes that play an important role in normal cardiac development and in some cases have pleiotropic effects on other organs. This work reviews some of the most common genetic causes of CHD as well as what is currently known about the underlying mechanisms.

Ontogeny of the facial phenotypic variability in Mexican patients with 22q11.2 deletion syndrome

Background

22q11.2 deletion syndrome is a medical condition that results from genomic loss at chromosome 22. Affected patients exhibit large variability that ranges from a severe condition to mild symptoms. In addition, the spectrum of clinical features differs among populations and even within family members. The facial features related to this syndrome are not an exception, and although part of its variation arises through development, few studies address this topic in order to understand the intra and inter-population heterogeneities. Here, we analyze the ontogenetic dynamics of facial morphology of Mexican patients with del22q11.2 syndrome.

Methods

Frontal facial photographs of 37 patients (mean age = 7.65 ± 4.21 SE) with del22q11.2DS and 200 control subjects (mean age = 7.69 ± 4.26 SE) were analyzed using geometric morphometric methods. Overall mean shape and size differences between patients and controls were analyzed, as well as differences in ontogenetic trajectories (i.e. development, growth, and allometry).

Results

We found that Mexican patients show typical traits that have been reported for the Caucasian population. Additionally, there were significant differences between groups in the facial shape and size when all the ontogenetic stages were considered together and, along ontogeny. The developmental and allometric trajectories of patients and controls were similar, but they differed in allometric scaling. Finally, patients and controls showed different growth trajectories.

Conclusion

The results suggest that the typical face of patients with del22q11.2DS is established prenatally; nonetheless, the postnatal ontogeny could influence the dysmorphology and its variability through size-related changes.

Genetic Basis for Congenital Heart Disease: Revisited: A Scientific Statement From the American Heart Association

This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientific statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish, as well as human induced pluripotent stem cell-based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care-related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.

Differences in the Tensor Veli Palatini Muscle and Hearing Status in Children With and Without 22q11.2 Deletion Syndrome

PURPOSE

To investigate the dimensions of the tensor veli palatini (TVP) muscle using high image resolution 3-dimensional magnetic resonance imaging (MRI) of the soft palate among children with normal velopharyngeal and craniofacial anatomy and to compare values to individuals with a diagnosis of 22q11.2 deletion syndrome (22q11DS). We also sought to determine whether there is a relationship between hypoplasia of the TVP and severity of middle ear dysfunction and hearing loss.

METHODS

Three-dimensional MRI were used to collect and analyze data obtained across 53 children between 4 and 12 years of age, including 40 children with normal velopharyngeal and craniofacial anatomy and 13 children with a diagnosis of 22q11.2 DS. Tensor veli palatini muscle length, thickness, and volume as well as bihamular distance were compared among participant groups.

RESULTS

A Welch's t-test revealed that the TVP in participants with 22q11DS is significantly shorter (P = .005, 17.3 vs 19.0 mm), thinner (P < .001, 1.1 vs 1.8 mm), and less voluminous (P < .001, 457.5 vs 667.3 mm³) than participants without 22q11DS. Participants with 22q11DS also had a greater (P = .006, 27.7 vs 24.7 mm) bihamular distance than participants without 22q11DS. There was an inverse relationship between TVP abnormalities noted above and the severity of audiologic and otologic histories.

CONCLUSION

The TVP muscle is substantially reduced in volume, length, and thickness in children with 22q11DS. These findings serve as preliminary support for the association of patient hearing and otologic severity and TVP dysmorphology.

Scoliosis in association with the 22q11.2 deletion syndrome: an observational study

OBJECTIVE

The 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion syndrome in humans. It is characterised by wide phenotypic variability, including congenital heart disease (CHD), immunodeficiency and scoliosis. However, little is known regarding the prevalence and characteristics of scoliosis in patients with 22q11.2DS. The objective of this study is to assess the prevalence of scoliosis, its characteristics and the association with CHD in patients with 22q11.2DS.

DESIGN

This prevalence study is based on physical examination and questionnaires of the world's largest 22q11.2DS longitudinal collected database (n=1393, Children's Hospital of Philadelphia) and was augmented with the scoliosis prevalence based on radiography in a smaller cohort (cross-sectional, University Medical Center Utrecht).

PATIENTS

Patients with a laboratory-confirmed 22q11.2 deletion who visited the specialised outpatient clinics were considered for inclusion.

MAIN OUTCOME MEASURES

(1) The prevalence of scoliosis, (2) its association with CHD, and (3) the similarity between 22q11.2DS curve patterns and adolescent idiopathic scoliosis (AIS) curve patterns.

RESULTS

Within the Philadelphia cohort, the prevalence of scoliosis in patients older than 16 years (n=317) was 48% (n=152). A similar prevalence (49%) was shown for the younger Utrecht cohort (n=97). The occurrence of scoliosis was not associated with the presence of CHD. Sixty-three per cent of patients with scoliosis had a scoliotic curve pattern that resembled AIS.

CONCLUSIONS

Clinicians should be aware that scoliosis is highly prevalent (48%-49%) in association with 22q11.2DS, irrespective of other clinical features (eg, the presence of CHD). Furthermore, 22q11.2DS may provide insights into the causes of AIS.

Exploratory study on cognitive abilities and social responsiveness in children with 22q11.2 deletion syndrome (22q11DS) and children with idiopathic intellectual disability (IID)

BACKGROUND

Development of cognitive skills and social responsiveness are areas of concern in children with 22q11.2 deletion syndrome (22q11DS). It remains unclear if the cognitive and social profiles and trajectories are syndrome-specific or similar to those of children with idiopathic intellectual disabilities (IID) with or without comorbid autism spectrum disorder (ASD).

AIMS AND METHODS

In this exploratory study, we examined and compared five broad cognitive abilities (BCAs) and the social responsiveness in primary school-aged children with 22q11DS (age 6-13, n = 21) and IQ-matched peers with IID (n = 21). The relative strengths and weaknesses of both groups were re-evaluated after 19 to 30 months.

OUTCOMES AND RESULTS

Four different cognitive trajectories (i.e. absolute progress, stability, growing into deficit, and absolute decline) were demonstrated in both groups. Most children showed combined types of trajectories across BCAs resulting in a complex changing cognitive profile. In the 22q11DS group, social responsiveness problems increased, whereas no significant change was observed in the IID group.

CONCLUSIONS AND IMPLICATIONS

Results reflect similar cognitive and social responsiveness profiles and trajectories across groups with children with 22q11DS being more at risk for growing into a social deficit. We recommend repeated monitoring of social skills development to adapt the environmental demands to the child's individual social capacities.

Development of quality metrics for ambulatory care in pediatric patients with tetralogy of Fallot

OBJECTIVE

The objective of this study was to develop quality metrics (QMs) relating to the ambulatory care of children after complete repair of tetralogy of Fallot (TOF).

DESIGN

A workgroup team (WT) of pediatric cardiologists with expertise in all aspects of ambulatory cardiac management was formed at the request of the American College of Cardiology (ACC) and the Adult Congenital and Pediatric Cardiology Council (ACPC), to review published guidelines and consensus data relating to the ambulatory care of repaired TOF patients under the age of 18 years. A set of quality metrics (QMs) was proposed by the WT. The metrics went through a two-step evaluation process. In the first step, the RAND-UCLA modified Delphi methodology was employed and the metrics were voted on feasibility and validity by an expert panel. In the second step, QMs were put through an "open comments" process where feedback was provided by the ACPC members. The final QMs were approved by the ACPC council.

RESULTS

The TOF WT formulated 9 QMs of which only 6 were submitted to the expert panel; 3 QMs passed the modified RAND-UCLA and went through the "open comments" process. Based on the feedback through the open comment process, only 1 metric was finally approved by the ACPC council.

CONCLUSIONS

The ACPC Council was able to develop QM for ambulatory care of children with repaired TOF. These patients should have documented genetic testing for 22q11.2 deletion. However, lack of evidence in the literature made it a challenge to formulate other evidence-based QMs.

Prevalence of hearing loss and clinical otologic manifestations in patients with 22q11.2 deletion syndrome: A literature review

BACKGROUND

Hearing loss and otitis media are frequently reported in patients with 22q11.2 deletion syndrome.

OBJECTIVE OF REVIEW

Our objective was to review the current literature on the prevalence of hearing loss and otologic manifestations in patients with 22q11.2 deletion syndrome.

TYPE OF REVIEW

Systematic review.

SEARCH STRATEGY

We conducted a systematic search in PubMed and Embase combining the term "22q11.2 deletion syndrome" and synonyms with "hearing loss" and "otologic manifestations" and synonyms.

EVALUATION METHOD

We screened title/abstract and full text of all retrieved articles on pre-defined in- and exclusion criteria. The remaining articles were assessed on risk of bias. Outcome measures included the prevalence of hearing loss and otologic manifestations such as otitis media.

RESULTS

Our search yielded 558 unique studies of which a total of 25 articles were included for critical appraisal and data extraction. Twenty-one studies reported on hearing loss, and 21 studies on otologic manifestations. The prevalence of hearing loss varied from 6.0% to 60.3%, where in most studies conductive hearing loss was most prevalent. Rates of recurrent or chronic otitis media varied from 2.2% to 89.8%.

CONCLUSION

Although a very broad range in prevalences is reported in different studies, hearing loss and recurrent or chronic otitis media are frequently present in patients with 22q11.2 deletion syndrome. Regular check-ups and audiometric testing are advised in these patients.

Incidence of the 22q11.2 deletion in a large cohort of miscarriage samples

Background

The 22q11.2 deletion syndrome is the most common microdeletion syndrome in livebirths, but data regarding its incidence in other populations is limited and also include ascertainment bias. This study was designed to determine the incidence of the 22q11.2 deletion in miscarriage samples sent for clinical molecular cytogenetic testing.

Results

Twenty-six thousand one hundred one fresh product of conception (POC) samples were sent to a CLIA- certified, CAP-accredited laboratory from April 2010–-May 2016 for molecular cytogenetic miscarriage testing using a single-nucleotide polymorphism (SNP)-based microarray platform. A retrospective review determined the incidence of the 22q11.2 deletion in this sample set. Fetal results were obtained in 22,451 (86%) cases, of which, 15 (0.07%) had a microdeletion in the 22q11.2 region (incidence, 1/1497). Of those, 12 (80%) cases were found in samples that were normal at the resolution of traditional karyotyping (i.e., had no chromosome abnormalities above 10 Mb in size) and three (20%) cases had additional findings (Trisomy 15, Trisomy 16, XXY). Ten (67%) cases with a 22q11.2 deletion had the common ~3 Mb deletion; the remaining 5 cases had deletions ranging in size from 0.65 to 1.5 Mb. A majority (12/15) of cases had a deletion on the maternally inherited chromosome. No significant relationship between maternal age and presence of a fetal 22q11.2 deletion was observed.

Conclusions

The observed incidence of 1/1497 for the 22q11.2 deletion in miscarriage samples is higher than the reported general population prevalence (1/4000–1/6000). Further research is needed to determine whether the 22q11.2 deletion is a causal factor for miscarriage.

Neuronal deficiency of ARV1 causes an autosomal recessive epileptic encephalopathy

We report an individual who presented with severe neurodevelopmental delay and an intractable infantile-onset seizure disorder. Exome sequencing identified a homozygous single nucleotide change that abolishes a splice donor site in the ARV1 gene (c.294 + 1G > A homozygous). This variant completely prevented splicing in minigene assays, and resulted in exon skipping and an in-frame deletion of 40 amino acids in primary human fibroblasts (NP_073623.1: p.(Lys59_Asn98del). The p.(Lys59_Asn98del) and previously reported p.(Gly189Arg) ARV1 variants were evaluated for protein expression and function. The p.(Gly189Arg) variant partially rescued the temperature-dependent growth defect in arv1Δ yeast, while p.(Lys59-Asn98del) completely failed to rescue at restrictive temperature. In contrast to wild type human ARV1, neither variant expressed detectable levels of protein in mammalian cells. Mice with a neuronal deletion of Arv1 recapitulated the human phenotype, exhibiting seizures and a severe survival defect in adulthood. Our data support ARV1 deficiency as a cause of autosomal recessive epileptic encephalopathy.

Exome sequencing analysis in a pair of monozygotic twins re-evaluates the genetics behind their intellectual disability and reveals a CHD2 mutation

BACKGROUND

Neurodevelopmental disorders include a broad spectrum of conditions, which are characterized by delayed motor and/or cognitive milestones and by a variable range of intellectual disability with or without an autistic behavior. Several genetic factors have been implicated in intellectual disability onset and exome sequencing studies have recently identified new inherited or de novo mutations in patients with neurodevelopmental disorders.

CASE

We report the case of two monozygotic twins who came for the first time to our attention at the age of 20months for a global neurodevelopmental delay associated with an autism spectrum disorder, hypotonia, postnatal microcephaly, stereotypic movements and circadian rhythm alterations in association with late-onset epilepsy. MECP2 sequence was normal. A CGH-array analysis revealed in both twins two maternally inherited duplications on chromosomes 8p22 and 16p13.11. The latter has been previously associated with neurodevelopmental disorders. We performed an exome sequencing analysis on one twin and her parents and identified a CHD2 mutation, previously described in association with a phenotypic spectrum overlapping our patients' phenotype.

CONCLUSIONS

This work underlines the importance to consider a CHD2 involvement in children with intellectual disability and autism spectrum disorder even in the absence of epilepsy at an early age. It also highlights the necessity to re-evaluate inherited copy number variants with low penetrance and/or high phenotypic variability because an underlying de novo molecular event can be the major cause of the phenotype. This is essential in order to reach a correct diagnosis and provide the couple with a proper recurrence risk.

Analysis of chromosome 22q11 copy number variations by multiplex ligation-dependent probe amplification for prenatal diagnosis of congenital heart defect

BACKGROUND

Congenital heart defects (CHD) represent one of the most common birth defects. This study aimed to evaluate the value of multiplex ligation-dependent probe amplification (MLPA) as a tool to detect the copy number variations (CNVs) of 22q11 in fetuses with CHD.

RESULTS

A large cohort of 225 fetuses with CHD was screened by fetal echocardiography. Once common chromosome abnormalities in 30 fetuses were screened out by conventional G-banding analysis, the CNVs of chromosome 22q11 in the remaining 195 fetuses were determined by MLPA for prenatal genetic counseling. In 195 CHD fetuses with normal karyotype, 11 cases had pathological CNVs, including 22q11.2 deletion (seven cases), the deletion of 22q11 cat eye syndrome (CES) region (one case), 22q11.2 duplication (one case), 22q13.3 deletion (one case) and 17p13.3 deletion (one case). In total, our findings from MLPA screening represented 4.9 % in our cohort. Among these, three cases were inherited CNVs, and eight cases were de novo. These CNVs were further verified by single nucleotide polymorphism (SNP)-array analysis, and their chromosomal location was refined.

CONCLUSION

This study indicated that MLPA could serve as an effective test for routine prenatal diagnosis of 22q11 in fetuses with CHD.

22q11.21 Deletion Syndromes: A Review of Proximal, Central, and Distal Deletions and Their Associated Features

Chromosome 22q11.21 contains a cluster of low-copy repeats (LCRs), referred to as LCR22A-H, that mediate meiotic non-allelic homologous recombination, resulting in either deletion or duplication of various intervals in the region. The deletion of the DiGeorge/velocardiofacial syndrome interval LCR22A-D is the most common recurrent microdeletion in humans, with an estimated incidence of ∼1:4,000 births. Deletion of other intervals in 22q11.21 have also been described, but the literature is often confusing, as the terms 'proximal', 'nested', 'distal', and 'atypical' have all been used to describe various of the other intervals. Individuals with deletions tend to have features with widely variable expressivity, even among families. This review concisely delineates each interval and classifies the reported literature accordingly.

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.

3 generation pedigree with paternal transmission of the 22q11.2 deletion syndrome: Intrafamilial phenotypic variability

In this case report, we present a paternal transmission of a classic 3 Mb 22q11.2 deletion syndrome (22q11.2 DS) in a 3 generation family. In this family a young girl, her father, her uncle and her grandfather were diagnosed with this disorder. All carriers showed phenotypic expression, there were no unaffected siblings in the second or third generation. Presenting symptoms in the patient in first generation (grandfather) were psoriatic arthritis, thrombocytopenia and a right aortic arch. There was no intellectual disability. The second generation uncle was known with a severe intellectual disability, mild facial characteristics, a septal defect and a clubfoot, whereas the second generation father had a tetralogy of Fallot, no intellectual disability and minimal facial characteristics. The third generation daughter had a moderate intellectual disability, hypernasal speech, triphalangeal thumb, severe speech and language development delay, pronounced facial characteristics and a diagnosis of ADHD. It was notable that the expression in the two brothers of the second generation gives two very different clinical phenotypes with a severe intellectual disability in the oldest brother. This report describes a pronounced clinical variability in a 3 generation familial 22q11.2 deletion with paternal transmission. We can assume that several mechanisms play an important role in the heterogeneity and part of the answer should be found in the genetic background underlying the 22q11.2 deletion. In addition in this family the neuropsychiatric phenotype and intellectual disability seem to be associated with a lower level of social and occupational functioning while a congenital heart disease does not. This clinical report illustrates that a detailed description of these patients can be very informative and still increase the knowledge on this heterogeneous syndrome. For the clinicians working with these patients it emphasizes the need for a multidisciplinary approach that takes into account the individual needs.

Clinical features and follow-up in patients with 22q11.2 deletion syndrome

OBJECTIVE

To investigate the clinical manifestations at diagnosis and during follow-up in patients with 22q11.2 deletion syndrome to better define the natural history of the disease.

STUDY DESIGN

A retrospective and prospective multicenter study was conducted with 228 patients in the context of the Italian Network for Primary Immunodeficiencies. Clinical diagnosis was confirmed by cytogenetic or molecular analysis.

RESULTS

The cohort consisted of 112 males and 116 females; median age at diagnosis was 4 months (range 0 to 36 years 10 months). The diagnosis was made before 2 years of age in 71% of patients, predominantly related to the presence of heart anomalies and neonatal hypocalcemia. In patients diagnosed after 2 years of age, clinical features such as speech and language impairment, developmental delay, minor cardiac defects, recurrent infections, and facial features were the main elements leading to diagnosis. During follow-up (available for 172 patients), the frequency of autoimmune manifestations (P = .015) and speech disorders (P = .002) increased. After a median follow-up of 43 months, the survival probability was 0.92 at 15 years from diagnosis.

CONCLUSIONS

Our data show a delay in the diagnosis of 22q11.2 deletion syndrome with noncardiac symptoms. This study provides guidelines for pediatricians and specialists for early identification of cases that can be confirmed by genetic testing, which would permit the provision of appropriate clinical management.

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.

The 22q11.2 deletion syndrome as a window into complex neuropsychiatric disorders over the lifespan

Evidence is rapidly accumulating that rare, recurrent copy number variants represent large effect risk factors for neuropsychiatric disorders. 22q11.2 deletion syndrome (22q11DS) (velocardiofacial syndrome or DiGeorge syndrome) is the most common known contiguous gene deletion syndrome and is associated with diverse neuropsychiatric disorders across the life span. One of the most intriguing aspects of the syndrome is the variability in clinical and cognitive presentation: children with 22q11DS have high prevalence of autism spectrum, attention deficit, and anxiety disorders, as well as psychotic-like features, and up to 30% of adolescents and adults develop schizophrenia-like psychosis. Recently, cases of early-onset Parkinson's disease in adults have been reported, collectively suggesting a role for disrupted dopaminergic neurotransmission in the observed neuropsychiatric phenotypes. There is also some evidence that 22q11DS-associated autism spectrum disorder and schizophrenia represent two unrelated phenotypic manifestations, consistent with a neuropsychiatric pleiotropy model. This genetic lesion thus provides a unique model for the discovery of specific genomic risk and (potentially) protective factors for neuropsychiatric disease. Here, we provide an overview of neuropsychiatric findings to date, which highlight the value of this syndrome in mapping the developmental trajectory of dimensional phenotypes that traverse multiple diagnostic categories. Potential sources of genetic variability that may contribute to the disorder's heterogeneous presentation are reviewed. Because of its known genetic etiology, animal models can readily be developed that recapitulate specific aspects of the syndrome. Future research directions involve translational models and potential for drug screenable targets in the context of this human model system.

Gastrointestinal involvement in patients affected with 22q11.2 deletion syndrome

OBJECTIVE. Enteropathy is a very common feature in patients with primary immunodeficiencies. In patients with Del22 gastrointestinal (GI) alterations, including feeding disorders and congenital abnormalities have been often reported, mostly in the first year of life. MATERIAL AND METHODS. Aim of this monocentric study is to better define the GI involvement in a cohort of 26 patients affected with Del22 syndrome. Anamnestic information was retrospectively collected for each patient. Weight and height parameters at the time of the screening were recorded. Plasma levels of hemoglobin, iron, ferritin, albumin, total protein, calcium, phosphorus, transaminase levels, antigliadin (AGA) IgA and IgG, and antitissue transglutaminase (anti-TGase) titers were measured. RESULTS. A GI involvement was identified in the 58% of patients. The prominent problems were abdominal pain, vomiting, gastroesophageal reflux and chronic constipation. Weight deficiency, short stature and failure to thrive were reported in 54, 42, and 30% of the patients, respectively. The evidence of sideropenic anemia, in keeping with hypoproteinemia, impaired acid steatocrit or cellobiose/mannitol test suggested an abnormal intestinal permeability. In this cohort, a high prevalence of AGA IgA and IgG positivity was observed. Celiac disease (CD) was suspected in three patients, and in one of them confirmed by histology. In this patient, a long-lasting gluten-free diet failed to restore the intestinal architecture. CONCLUSIONS. In conclusion, GI involvement is a very common feature in Del22 patients. A better characterization of GI involvement would be very useful to improve the management of these patients.

Intergenerational and intrafamilial phenotypic variability in 22q11.2 deletion syndrome subjects

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a common microdeletion syndrome, which occurs in approximately 1:4000 births. Familial autosomal dominant recurrence of the syndrome is detected in about 8-28% of the cases. Aim of this study is to evaluate the intergenerational and intrafamilial phenotypic variability in a cohort of familial cases carrying a 22q11.2 deletion.

METHODS

Thirty-two 22q11.2DS subjects among 26 families were enrolled.

RESULTS

Second generation subjects showed a significantly higher number of features than their transmitting parents (212 vs 129, P = 0.0015). Congenital heart defect, calcium-phosphorus metabolism abnormalities, developmental and speech delay were more represented in the second generation (P < 0.05). Ocular disorders were more frequent in the parent group. No significant difference was observed for the other clinical variables. Intrafamilial phenotypic heterogeneity was identified in the pedigrees. In 23/32 families, a higher number of features were found in individuals from the second generation and a more severe phenotype was observed in almost all of them, indicating the worsening of the phenotype over generations. Both genetic and epigenetic mechanisms may be involved in the phenotypic variability.

CONCLUSIONS

Second generation subjects showed a more complex phenotype in comparison to those from the first generation. Both ascertainment bias related to patient selection or to the low rate of reproductive fitness of adults with a more severe phenotype, and several not well defined molecular mechanism, could explain intergenerational and intrafamilial phenotypic variability in this syndrome.

Prevalence of selected genomic deletions and duplications in a French-Canadian population-based sample of newborns

Chromosomal microarray analysis has identified many novel microdeletions or microduplications that produce neurodevelopmental disorders with a recognizable clinical phenotype and that are not observed in normal individuals. However, imbalance of other genomic regions is associated with a variable phenotype with intellectual disability (ID) or autism in some individuals but are also observed in completely normal individuals. Several large studies have reported the prevalence of copy number (CN) variants in people with particular features (e.g., ID, autism, schizophrenia, or epilepsy); few studies have investigated the prevalence of genomic CN changes in the general population. We used a high-throughput method to screen 6813 consecutive cord blood samples from a predominantly French–Canadian population to assess genomic CN in five genomic regions: 1p36, 15q11-q13, 16p11.2, 16p11.2-p12.2, and 22q11.2. We identified one deletion and one duplication within 1p36, two deletions of 15q11-q13, eight deletions of 16p11.2-p12.2, two deletions and five duplications of 16p11.2, and six duplications of 22q11.2. This study provides estimates of the frequency of CN variants in an unselected population. Our findings have important implications for genetic counseling.

Speech and hearing in adults with 22q11.2 deletion syndrome

The purpose of the study was to investigate the prevalence of velopharyngeal impairment, compensatory articulation, reduced intelligibility, and to rate the general impression of speech in adults with 22q11.2 deletion syndrome. The second purpose was to study the prevalence and type of hearing impairment in these adults. A referred, consecutive series of 24 adults with confirmed 22q11.2 deletion, 16 female and 8 males, with a mean age of 25 years (19-38 years) was included in the study. A blind assessment of speech by three experienced speech-language pathologists was performed. Sixteen (66%) patients had a mild to severe velopharyngeal impairment. The most prevalent symptoms of velopharygeal impairment were hypernasality and audible nasal airflow. The mean nasalance score was 33% (6-66%). Only two patients had disordered articulation; one of these had glottal articulation. A mean of 96% (88-100%) of single words were rated to be intelligible. To achieve these results half of the patients previously had velopharyngeal flap surgery. Forty-one percent (9/22) had mild-moderate hearing impairment; three had sensorineural type, four conductive and two had a mixed type. In conclusion the majority of the patients had no articulation errors and good intelligibility; while one-third still had moderate to severe problems with velopharyngeal impairment. Around 40% still had some hearing impairment, in most cases with a mild to moderate conductive component. Thus, a high prevalence of speech and hearing problems seems to be a part of the phenotype in adults with 22q11.2DS.

Clinical applications of schizophrenia genetics: genetic diagnosis, risk, and counseling in the molecular era

Schizophrenia is a complex neuropsychiatric disease with documented clinical and genetic heterogeneity, and evidence for neurodevelopmental origins. Driven by new genetic technologies and advances in molecular medicine, there has recently been concrete progress in understanding some of the specific genetic causes of this serious psychiatric illness. In particular, several large rare structural variants have been convincingly associated with schizophrenia, in targeted studies over two decades with respect to 22q11.2 microdeletions, and more recently in large-scale, genome-wide case-control studies. These advances promise to help many families afflicted with this disease. In this review, we critically appraise recent developments in the field of schizophrenia genetics through the lens of immediate clinical applicability. Much work remains in translating the recent surge of genetic research discoveries into the clinic. The epidemiology and basic genetic parameters (such as penetrance and expression) of most genomic disorders associated with schizophrenia are not yet well characterized. To date, 22q11.2 deletion syndrome is the only established genetic subtype of schizophrenia of proven clinical relevance. We use this well-established association as a model to chart the pathway for translating emerging genetic discoveries into clinical practice. We also propose new directions for research involving general genetic risk prediction and counseling in schizophrenia.

Phenotypic variability of distal 22q11.2 copy number abnormalities

The availability of microarray technology has led to the recent recognition of copy number abnormalities of distal chromosome 22q11.2 that are distinct from the better-characterized deletions and duplications of the proximal region. This report describes five unrelated individuals with copy number abnormalities affecting distal chromosome 22q11.2. We report on novel phenotypic features including diaphragmatic hernia and uterine didelphys associated with the distal microdeletion syndrome; and frontomedial polymicrogyria and callosal agenesis associated with the distal microduplication syndrome. We describe the third distal chromosome 22q11.2 microdeletion patient with Goldenhar syndrome. Patients with distal chromosome 22q11.2 copy number abnormalities exhibit inter- and intra-familial phenotypic variability, and challenge our ability to draw meaningful genotype-phenotype correlations.

22q11.2 deletion presenting with severe hypocalcaemia, seizure and basal ganglia calcification in an adult man

We report a 40-year-old man who was found to have profound hypocalcaemia and hypoparathyroidism when investigated for multiple, generalized, tonic/clonic seizures and a chest infection. Computed tomography scan of the brain revealed extensive symmetric bilateral calcification within the cerebellum, thalamus and basal ganglia. Molecular cytogenetic testing by fluorescent in situ hybridization using the commercial Vysis LSI DiGeorge/VCFS dual colour probe set showed a deletion of 22q11.2. The extraordinary feature of this case is the adult presentation of hypocalcaemia, hypoparathyroidism and basal ganglia calcification due to 22q11.2 deletion.

Genetic dosage compensation in a family with velo-cardio-facial/DiGeorge/22q11.2 deletion syndrome

Cytogenetic studies of a male child carrying the 22q11.2 deletion common in patients with velo-cardio-facial/DiGeorge syndrome showed an unexpected rearrangement of the 22q11.2 region in his normal appearing mother. The mother carried a 3 Mb deletion on one copy and a reciprocal, similar sized duplication on the other copy of chromosome 22q11.2 as shown by fluorescence in situ hybridization and array comparative genome hybridization analyses. The most parsimonious mechanism for the rearrangement is a mitotic non-allelic homologous recombination event in a cell in the early embryo soon after fertilization. The normal phenotype of the mother can be explained by the theory of genetic dosage compensation. This is the second documented case of such an event for this or any genomic disorder. This finding helps to reinforce this phenomenon in a human model, and has significant implications for recurrence risks for the dose-compensated mother.

Complex congenital heart disease in unaffected relatives of adults with 22q11.2 deletion syndrome

The 22.q11.2 deletion syndrome (22q11DS) is a common genetic condition associated with 22q11.2 microdeletions and classically has included congenital heart disease (CHD) as a part of the variable expression. Some evidence has shown that relatives of those with 22q11DS might be at an increased risk of CHD in the absence of 22q11.2 deletions. We obtained a detailed family history of CHD in the first- to third-degree relatives (n = 2,639) of 104 adult probands with 22q11DS. We compared the prevalence of CHD in the relatives without 22q11.2 deletions to the published general population prevalence. We also investigated the effect of CHD in the probands on prevalence of CHD in the relatives. Of the 104 probands with 22q11DS, 14 (13.5%) had 17 relatives (17 of 2,639, 0.6%) with CHD. Of 66 probands with CHD, 15 (0.9%) of their 1,663 relatives had CHD, a significantly greater prevalence than that for the relatives of probands without CHD (0.2%, 2 of 976, p = 0.041, odds ratio 4.43, 95% confidence interval 1.03 to 40.00). In relatives of probands with CHD, the prevalence of those with severe CHD (0.36%) was significantly elevated compared to population expectations (0.061%, p = 0.007, odds ratio 5.88, 95% confidence interval 2.16 to 12.85). In conclusion, these results support a heritable susceptibility to CHD in families of probands with 22q11DS, in addition to that imparted by microdeletion 22q11.2. The occurrence of CHD in relatives might be related to the expression of CHD in the proband with 22q11DS. These findings have potential implications for the genetic counseling of families of those with 22q11DS and support the notion that interacting genetic variants might contribute to the variable expression of 22q11DS.

Frequency of 22q11.2 microdeletion in children with congenital heart defects in western poland

BACKGROUND

The 22q11.2 microdeletion syndrome (22q11.2 deletion syndrome -22q11.2DS) refers to congenital abnormalities, including primarily heart defects and facial dysmorphy, thymic hypoplasia, cleft palate and hypocalcaemia. Microdeletion within chromosomal region 22q11.2 constitutes the molecular basis of this syndrome. The 22q11.2 microdeletion syndrome occurs in 1/4000 births. The aim of this study was to determine the frequency of 22q11.2 microdeletion in 87 children suffering from a congenital heart defect (conotruncal or non-conotruncal) coexisting with at least one additional 22q11.2DS feature and to carry out 22q11.2 microdeletion testing of the deleted children's parents. We also attempted to identify the most frequent heart defects in both groups and phenotypic traits of patients with microdeletion to determine selection criteria for at risk patients.

METHODS

The analysis of microdeletions was conducted using fluorescence in situ hybridization (FISH) on metaphase chromosomes and interphase nuclei isolated from venous peripheral blood cultures. A molecular probe (Tuple) specific to the HIRA (TUPLE1, DGCR1) region at 22q11 was used for the hybridisation.

RESULTS

Microdeletions of 22q11.2 region were detected in 13 children with a congenital heart defect (14.94% of the examined group). Microdeletion of 22q11.2 occurred in 20% and 11.54% of the conotruncal and non-conotruncal groups respectively. Tetralogy of Fallot was the most frequent heart defect in the first group of children with 22q11.2 microdeletion, while ventricular septal defect and atrial septal defect/ventricular septal defect were most frequent in the second group. The microdeletion was also detected in one of the parents of the deleted child (6.25%) without congenital heart defect, but with slight dysmorphism. In the remaining children, 22q11.2 microdeletion originated de novo.

CONCLUSIONS

Patients with 22q11.2DS exhibit wide spectrum of phenotypic characteristics, ranging from discreet to quite strong. The deletion was inherited by one child. Our study suggests that screening for 22q11.2 microdeletion should be performed in children with conotruncal and non-conotruncal heart defects and with at least one typical feature of 22q11.2DS as well as in the deleted children's parents.

Age-dependent clinical problems in a Norwegian national survey of patients with the 22q11.2 deletion syndrome

Patients with the 22q11.2 deletion syndrome display a wide phenotypic variation that is important for clinical follow-up. In this national survey of 60 patients (ages 1 to 54 years) diagnosed by Fluorescence in situ hybridization test, data were collected from medical records, a physical examination, and a semistructured interview. Ultrasound investigation of the kidneys was also performed. In addition, multiplex ligation probe amplification assay was performed to detect deletion size. Phenotypic features leading to the genetic diagnosis were noted. The patients showed a variety of organ malformations including 39 with heart anomalies. Only 20 individuals had been diagnosed with 22q11.2 DS in the first year of life. Four patients had renal and five males had genital malformations. The increased infection susceptibility (excluding otitis media) and most feeding difficulties subsided during early childhood. Speech difficulties started early and were a major problem for many patients at least until 10 years of age. Ten patients developed kyphoscoliosis in late childhood. In teenagers and adults, abnormal social behavior, learning disabilities, and psychiatric symptoms dominated. Our study which also includes adult patients emphasizes a marked change in challenges in individuals with the 22q11.2 deletion syndrome with increasing age.

Further delineation of the 15q13 microdeletion and duplication syndromes: a clinical spectrum varying from non-pathogenic to a severe outcome

BACKGROUND

Recurrent 15q13.3 microdeletions were recently identified with identical proximal (BP4) and distal (BP5) breakpoints and associated with mild to moderate mental retardation and epilepsy.

METHODS

To assess further the clinical implications of this novel 15q13.3 microdeletion syndrome, 18 new probands with a deletion were molecularly and clinically characterised. In addition, we evaluated the characteristics of a family with a more proximal deletion between BP3 and BP4. Finally, four patients with a duplication in the BP3-BP4-BP5 region were included in this study to ascertain the clinical significance of duplications in this region.

RESULTS

The 15q13.3 microdeletion in our series was associated with a highly variable intra- and inter-familial phenotype. At least 11 of the 18 deletions identified were inherited. Moreover, 7 of 10 siblings from four different families also had this deletion: one had a mild developmental delay, four had only learning problems during childhood, but functioned well in daily life as adults, whereas the other two had no learning problems at all. In contrast to previous findings, seizures were not a common feature in our series (only 2 of 17 living probands). Three patients with deletions had cardiac defects and deletion of the KLF13 gene, located in the critical region, may contribute to these abnormalities. The limited data from the single family with the more proximal BP3-BP4 deletion suggest this deletion may have little clinical significance. Patients with duplications of the BP3-BP4-BP5 region did not share a recognisable phenotype, but psychiatric disease was noted in 2 of 4 patients.

CONCLUSIONS

Overall, our findings broaden the phenotypic spectrum associated with 15q13.3 deletions and suggest that, in some individuals, deletion of 15q13.3 is not sufficient to cause disease. The existence of microdeletion syndromes, associated with an unpredictable and variable phenotypic outcome, will pose the clinician with diagnostic difficulties and challenge the commonly used paradigm in the diagnostic setting that aberrations inherited from a phenotypically normal parent are usually without clinical consequences.

Autism, ADHD, mental retardation and behavior problems in 100 individuals with 22q11 deletion syndrome

This study assessed the prevalence and type of associated neuropsychiatric problems in children and adults with 22q11 deletion syndrome. One-hundred consecutively referred individuals with 22q11 deletion syndrome were given in-depth neuropsychiatric assessments and questionnaires screens. Autism spectrum disorders (ASDs) and/or attention deficit/hyperactivity disorder (ADHD) were diagnosed in 44 cases. ASD was diagnosed in 23 cases of whom only 5 had autistic disorder. ADHD was diagnosed in 30 individuals. In nine of these cases with ASD or ADHD there was a combination of these diagnoses. Mental retardation (MR) with or without ASD/ADHD was diagnosed in 51 individuals. ASD, ADHD, and/or MR were present in 67 cases. Females had higher IQ than males. The results of this study showed that the vast majority of all individuals with 22q11 deletion syndrome have behavior and/or learning problems and more than 40% meet criteria for either ASD, ADHD or both. Neuropsychiatric and neuropsychological evaluations are indicated as parts of the routine clinical assessment of individuals with 22q11 deletion syndrome.

Síndrome de deleção 22q11.2: compreendendo o CATCH22

OBJETIVO:Realizar uma revisão dos aspectos históricos, epidemiológicos, clínicos, etiológicos e laboratoriais da síndrome de deleção 22q11.2, salientando-se a importância e as dificuldades do seu diagnóstico. FONTES DE DADOS: Pesquisa nas bases de dados Medline, Lilacs e SciELO, além da Internet e capítulos de livros em inglês, acerca de publicações feitas entre 1980 e 2008. Para isso, utilizaram-se os descritores "22q11", "DiGeorge", "Velocardiofacial" e "CATCH22". SÍNTESE DOS DADOS: A síndrome de deleção 22q11.2, também conhecida como síndrome de DiGeorge ou velocardiofacial, foi identificada no começo da década de 1990. A microdeleção 22q11.2 é considerada uma das síndromes de microdeleção genética mais frequentes em seres humanos. Caracteriza-se por um espectro fenotípico bastante amplo, com mais de 180 achados clínicos já descritos do ponto de vista físico e comportamental. Contudo, nenhum achado é patognomônico ou mesmo obrigatório. A maioria dos pacientes apresenta uma deleção pequena, detectada somente por técnicas de genética molecular, como a hibridização in situ fluorescente. Apresenta padrão de herança autossômico dominante, ou seja, indivíduos acometidos apresentam um risco de 50% de transmiti-la a seus filhos. CONCLUSÕES: Pacientes com a síndrome de deleção 22q11.2 frequentemente necessitam, ao longo de suas vidas, de um grande número de intervenções médicas e hospitalizações. O diagnóstico precoce é fundamental para a adequada avaliação e manejo clínico dos indivíduos e seus familiares.