The Outcomes of Cardiac Surgery in Children With DiGeorge Syndrome in a Single Center Experience: A Retrospective Cohort Study

Background DiGeorge syndrome, a common genetic microdeletion syndrome, is associated with multiple congenital anomalies, including congenital cardiac diseases. This study aims to identify the short and midterm outcomes of cardiac surgery performed on children with DiGeorge syndrome. Methods A retrospective cohort study was conducted between the period of 2018-2022, which included children divided into two groups with a 1:2 ratio. Group one included DiGeorge syndrome patients who were diagnosed using fluorescence in situ hybridization (FISH). Group two included the control group of patients who were clear of genetic syndromes. The two groups were matched based on similar cardiac surgery, age of surgery, and Risk Adjustment in Congenital Heart Surgery (RACHS-1) score. The two groups were compared based on the demographical data and postoperative complications. Results The study consisted of 81 children; 27 were DiGeorge syndrome patients, and 54 were in the control group. DiGeorge syndrome patients showed an increase in mechanical ventilation duration (p=0.0047), intensive care unit (ICU) length of stay (p=0.0012), and hospital length of stay (p=0.0391). Moreover, they showed an increased risk for bacteremia (p=0.0414), ventilator-associated pneumonia (VAP; p=0.0036), urinary tract infections (UTI; p=0.0064), and surgical site infection (SSI; p≤0.0001). They were also more susceptible to postoperative seizures (p=0.0049). Furthermore, patients with DiGeorge syndrome had a higher prevalence of congenital renal anomalies. However, there was no mortality in either group.  Conclusion This study shows a variability in the postoperative outcomes between the two groups. The study demonstrates that patients with DiGeorge syndrome have higher risks of infections and longer hospital stay during the postoperative period. Further research with a larger sample is needed to confirm our findings.

Late-Onset 22q11.2 Deletion Syndrome With Mild Cardiac Phenotype: A Unique Adult Presentation Diagnosed at 45 Years of Age

This case report presents a detailed exploration of an adult-onset 22q11 deletion syndrome, a rare genetic disorder typically diagnosed in children. The report highlights the diagnostic challenges posed by this atypical presentation, emphasizing the need for clinicians to consider such conditions in differential diagnoses, especially in adults. This case is remarkable for its late onset and mild symptoms, which significantly deviated from the common pediatric presentation, including hypocalcemia due to hypoparathyroidism and a fenestrated atrial septal defect without significant hemodynamic implications. The importance of recognizing the broad phenotypic variability of the syndrome and the implications for clinical practice are discussed, providing insights into the genetic and phenotypic diversity of the condition. In conclusion, this case illuminates the diverse clinical spectrum of adult-onset 22q11 deletion syndrome, emphasizing its relevance to clinical practice.

22q11.2 Deletion Syndrome Diagnosed 47 Years After Surgery for Tetralogy of Fallot

A 51-year-old man presented with severe hydrocele testis, dyspnea on exertion, and systemic edema. He had a history of surgery for tetralogy of Fallot (TOF). On the second day of admission, he presented with severe nose bleeding followed by CO2 narcosis. Blood gas analysis revealed an extremely low level of Ca2+. An echocardiogram revealed an excessively enlarged right ventricle and severe pulmonary valve regurgitation (PR). Hypocalcemia, history of TOF, and characteristic facial features suggested 22q11.2 deletion syndrome, which was confirmed by fluorescence in-situ hybridization (FISH) chromosome test. Open heart redo-surgery was performed for severe PR. The surgery revealed a severely hypoplastic pulmonary valve, which is characteristic of 22q11.2 deletion syndrome. 22q11.2 syndrome thus could be overlooked until age over 50 and therefore become critical.

A model for preservation of thymocyte-depleted thymus

DiGeorge syndrome is a disorder caused by a microdeletion on the long arm of chromosome 22. Approximately 1% of patients diagnosed with DiGeorge syndrome may have an absence of a functional thymus, which characterizes the complete form of the syndrome. These patients require urgent treatment to reconstitute T cell immunity. Thymus transplantation is a promising investigational procedure for reconstitution of thymic function in infants with congenital athymia. Here, we demonstrate a possible optimization of the preparation of thymus slices for transplantation through prior depletion of thymocytes and leukocyte cell lineages followed by cryopreservation with cryoprotective media (5% dextran FP 40, 5% Me2SO, and 5% FBS) while preserving tissue architecture. Thymus fragments were stored in liquid nitrogen at -196°C for 30 days or one year. The tissue architecture of the fragments was preserved, including the distinction between medullary thymic epithelial cells (TECs), cortical TECs, and Hassall bodies. Moreover, depleted thymus fragments cryopreserved for one year were recolonized by intrathymic injections of 3×106 thymocytes per mL, demonstrating the capability of these fragments to support T cell development. Thus, this technique opens up the possibility of freezing and storing large volumes of thymus tissue for immediate transplantation into patients with DiGeorge syndrome or atypical (Omenn-like) phenotype.

DiGeorge Syndrome With Absence of Speech: A Rare Case

DiGeorge syndrome (DGS) is a rare genetic disorder caused by a deletion or abnormality of a small piece of chromosome 22. This condition can affect multiple organs in the body, including the heart, thymus, and parathyroid glands. While speech and language difficulties are common in individuals with DGS, the complete absence of speech is a rare presentation. This case report presents the clinical features and management of a child with DGS who presented with an absence of speech. The child underwent a multidisciplinary intervention approach, including speech and language therapy, occupational therapy, and special education, to improve their communication skills, motor coordination, sensory integration, academic performance, and social skills. The interventions resulted in some improvement in their overall function; however, speech improvement was not significant. This case report contributes to the literature on DGS by highlighting the potential underlying causes of speech and language difficulties in patients with this condition, and the possible etiologies that may lead to a complete absence of speech, which is a severe manifestation. It also emphasizes the importance of early recognition and intervention with a multidisciplinary approach to management, as early intervention can lead to better outcomes for patients with DGS.

Insufficiency of Mrpl40 disrupts testicular structure and semen parameters in a murine model

Approximately 31% of patients with 22q11.2 deletion syndrome (22q11.2DS) have genitourinary system disorders and 6% of them have undescended testes. Haploinsufficiency of genes on chromosome 22q11.2 might contribute to the risk of 22q11.2DS. In this study, we used mice with single-allele deletion in mitochondrial ribosomal protein L40 (Mrpl40 +/- ) as models to investigate the function of Mrpl40 in testes and spermatozoa development. The penetrance of cryptorchidism in Mrpl40 +/- mice was found to be higher than that in wild-type (WT) counterparts. Although the weight of testes was not significantly different between the WT and Mrpl40 +/- mice, the structure of seminiferous tubules and mitochondrial morphology was altered in the Mrpl40 +/- mice. Moreover, the concentration and motility of spermatozoa were significantly decreased in the Mrpl40 +/- mice. In addition, data-independent acquisition mass spectrometry indicated that the expression of genes associated with male infertility was altered in Mrpl40 +/- testes. Our study demonstrated the important role of Mrpl40 in testicular structure and spermatozoa motility and count. These findings suggest that Mrpl40 is potentially a novel therapeutic target for cryptorchidism and decreased motility and count of spermatozoa.

Fever of Unknown Origin Reveals a Missed Diagnosis of DiGeorge Syndrome in a 21-Year-Old Female

DiGeorge syndrome, caused by a microdeletion of the 22q11.2 region of chromosome 22, is a relatively rare condition. This syndrome can be difficult to recognize because a constellation of symptoms show different presentations. Most individuals diagnosed with this condition are identified in early childhood. With the emergence of new screening techniques, even fewer individuals with this syndrome are missed. Prior to these screening techniques, it was uncommon for patients to be diagnosed in adulthood. As a result, many internists, who focus only on the adult population, are unlikely to recognize and diagnose DiGeorge syndrome as the patient ages merely because it is not commonly diagnosed later in life. Early recognition and management are essential for the treatment of this condition. Here, we present the case of a 21-year-old woman diagnosed with DiGeorge syndrome as an adult.

Gastrointestinal Features of 22q11.2 Deletion Syndrome Include Chronic Motility Problems From Childhood to Adulthood

OBJECTIVES

22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion syndrome and has a multisystemic presentation including gastrointestinal features that have not yet been fully described. Our aim was to examine lifetime gastrointestinal problems in a large cohort of patients with 22q11.2DS.

METHODS

All patients followed in the 22q and You Center at the Children's Hospital of Philadelphia (n = 1421) were retrospectively screened for: 1) age ≥ 17 years, 2) documented chromosomal microdeletion within the 22q11.2 LCR22A-LCR22D region, and 3) sufficient clinical data to characterize the adult gastrointestinal phenotype. Gastrointestinal problems in childhood, adolescence, and adulthood were summarized. Statistical association testing of symptoms against other patient characteristics was performed.

RESULTS

Included patients (n = 206; 46% female; mean age, 27 years; median follow-up, 21 years) had similar clinical characteristics to the overall cohort. Genetic distribution was also similar, with 96% having deletions including the critical LCR22A-LCR22B segment (95% in the overall cohort). Most patients experienced chronic gastrointestinal symptoms in their lifetime (91%), but congenital gastrointestinal malformations (3.5%) and gastrointestinal autoimmune diseases (1.5%) were uncommon. Chronic symptoms without anatomic or pathologic abnormalities represented the vast burden of illness. Chronic symptoms in adulthood are associated with other chronic gastrointestinal symptoms and psychiatric comorbidities ( P < 0.01) but not with deletion size or physiologic comorbidities ( P > 0.05). One exception was increased nausea/vomiting in hypothyroidism ( P = 0.002).

CONCLUSIONS

Functional gastrointestinal disorders (FGIDs) are a common cause of ill health in children and adults with 22q11.2DS. Providers should consider screening for the deletion in patients presenting with FGIDs and associated comorbidities such as neuropsychiatric illness, congenital heart disease, and palatal abnormalities.

Hybrid Single-Stage Repair of Kommerell's Diverticulum in a Right Aortic Arch in a Patient With 22q11.2 Deletion Syndrome

Hybrid single-stage repair of Kommerell's diverticulum in a right aortic arch.Aortic arch anomalies, isolated or associated with congenital heart defects, are cardiovascular manifestations frequently associated with 22q11.2 deletion syndrome. Kommerell's diverticulum in the context of a right aortic arch is an exceedingly rare congenital anomaly, consisting in aneurysmal degeneration of the origin of an aberrant left subclavian artery. Open surgical repair has been the treatment paradigm, but in recent years, hybrid and endovascular procedures have also been proposed. In this report we present the case of a patient affected by 22q11.2 deletion syndrome successfully treated for Kommerell's diverticulum associated with a right-sided aortic arch through a single-stage hybrid procedure, consisting of bilateral carotid-subclavian bypass, exclusion of the diverticulum by an endovascular thoracic stent graft, and aberrant left subclavian artery plug occlusion. This type of hybrid technique can be an excellent alternative to extensive open surgical repairs or when total endovascular repair is deemed unachievable, also in the context of a complex genetic syndrome.

Evaluation and Maintenance of Behavioral Interventions for 22q11.2 Deletion Syndrome

22q11.2-deletion syndrome is a genetic disorder caused by a small deletion of chromosome 22. This deletion often results in developmental delays, learning disabilities, medical conditions, and comorbid psychiatric conditions. Patients with 22q11.2DS may present with a variety of behavioral phenotypes including obsessiveness and rigidity, poor social skills, and anxiety. In some cases, the phenotype can consist of destructive and inappropriate behavior including harming self and others. Behavioral difficulties are reported as one of the most challenging aspects of 22q11.2-deletion syndrome for families of patients, however, few studies have examined behavioral interventions as a possible therapeutic treatment for this population. Using principles derived from operant-behavioral psychology, we conducted functional assessments to determine the environmental correlates of destructive and inappropriate behaviors in two adult men with 22q11.2-deletion syndrome. Subsequently, behavioral interventions based on differential reinforcement were incorporated into each participant's natural environment to eliminate these behaviors. Significant reductions in destructive and inappropriate behavior were observed with both participants and therapeutic gains were maintained at follow-up. We discuss the role of behavioral interventions in combination with appropriate psychotropic medication when addressing challenging behaviors in this population.

The Prevalence of Congenital Heart Diseases in Syndromic Children at King Khalid National Guard Hospital from 2005 to 2016

Background Congenital heart diseases (CHDs) are abnormalities that present in the heart since birth and are one of the leading causes of infant mortality in the world. CHDs are more common among children with dysmorphic syndromes. The current study aims to estimate the prevalence of many CHDs in different dysmorphic syndromes. Methods This was a retrospective chart review study conducted on all dysmorphic syndrome patients who attended genetic clinics at King Khalid National Guard Hospital in King Abdulaziz Medical City (KAMC), Jeddah, Saudi Arabia from 2005 to 2016. Dysmorphic pediatric patients less than 14 years old who had genetic testing to confirm their diagnosis were included in the study. Patients who did not have any previous echocardiography were excluded. Results A total of 212 individuals (47% males and 53% females) were included. Eighty-five percent of Down syndrome patients had CHDs, and the most common CHD was an atrial septal defect (ASD) (51%). In patients with Turner syndrome, 45% of them had CHDs, and bicuspid aortic valve (BAV) (40%) was the most common defect. In DiGeorge syndrome, 81% of patients had CHDs, and ventricular septal defect (VSD) (41%) was the most common. In Williams syndrome, 83% of patients had CHDs. All patients with Noonan, Edwards, CHARGE (coloboma, heart defects, atresia choanae (also known as choanal atresia), growth retardation, genital abnormalities, and ear abnormalities), and Rubinstein-Taybi syndromes were found to have CHDs. In Patau syndrome and Joubert syndrome, 50% of patients in each had CHDs. Patients with Prader Willi syndrome had normal findings in the echocardiogram. Conclusion The highest prevalence of CHDs was found in Down syndrome. This study has a significant impact on the future of managing and directing the resources to improve the quality of life for syndromic patients. Further studies are needed to confirm these findings and to increase the local data in the field of CHDs in Saudi Arabia among syndromic patients.

Schizophrenia in DiGeorge Syndrome: A Unique Case Report

Herein we present the unique case of a 21-year-old African American woman who presented with psychotic features and the incidental finding of basal ganglia calcifications on computed tomography (CT) scan of the head. She was initially presumed to have Fahr's syndrome in the context of idiopathic bilateral basal ganglia calcifications and psychotic features. Genetic testing performed revealed the deletion of 22q11.2, thus establishing the diagnosis of DiGeorge syndrome. This case highlights the importance of noticing subtle physical exam findings along with laboratory findings as this led to the diagnosis of DiGeorge syndrome for this patient. This case is unique in two aspects; first, the finding of basal ganglia calcification via CT of the brain in patients with DiGeorge syndrome has rarely been reported in the literature. Second, this case highlights the strong genetic predisposition for schizophrenia in patients with DiGeorge syndrome.

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.

The effect of hypocalcemia in early childhood on autism-related social and communication skills in patients with 22q11 deletion syndrome

22q11 deletion syndrome (22qDS), also known as DiGeorge syndrome, is a copy number variant disorder that has a diverse clinical presentation including hypocalcaemia, learning disabilities, and psychiatric disorders. Many patients with 22q11DS present with signs that overlap with autism spectrum disorder (ASD) yet the possible physiological mechanisms that link 22q11DS with ASD are unknown. We hypothesized that early childhood hypocalcemia influences the neurobehavioral phenotype of 22q11DS. Drawing on a longitudinal cohort of 22q11DS patients, we abstracted albumin-adjusted serum calcium levels from 151 participants ranging in age from newborn to 19.5 years (mean 2.5 years). We then examined a subset of 20 infants and toddlers from this group for the association between the lowest calcium level on record and scores on the Communication and Symbolic Behavior Scales-Developmental Profile Infant-Toddler Checklist (CSBS-DP ITC). The mean (SD) age at calcium testing was 6.2 (8.5) months, whereas the mean (SD) age at the CSBS-DP ITC assessment was 14.7 (3.8) months. Lower calcium was associated with significantly greater impairment in the CSBS-DP ITC Social (p < 0.05), Speech (p < 0.01), and Symbolic domains (p < 0.05), in regression models adjusted for sex, age at blood draw, and age at the psychological assessment. Nevertheless, these findings are limited by the small sample size of children with combined data on calcium and CSBS-DP ITC, and hence will require replication in a larger cohort with longitudinal assessments. Considering the role of calcium regulation in neurodevelopment and neuroplasticity, low calcium during early brain development could be a risk factor for adverse neurobehavioral outcomes.

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.

22q11.2 Deletion syndrome is associated with increased perioperative events and more complicated postoperative course in infants undergoing infant operative correction of truncus arteriosus communis or interrupted aortic arch

OBJECTIVE

The effect of genotype on the outcomes of infant cardiac operations has not been well established. The purpose of the present study was to investigate the effect of 22q11.2 deletion (22q11del) on infants with truncus arteriosus communis (TA) and interrupted aortic arch (IAA) undergoing operative correction during infancy.

METHODS

We conducted a retrospective cohort study of all infants who had undergone operative correction of TA or IAA at the Children's Hospital of Philadelphia from 1995 to 2007, comparing the perioperative outcomes (hospital length of stay, intensive care, mechanical ventilation, risk of cardiac and noncardiac events, number of consultations, and number of discharge medications) by 22q11del status.

RESULTS

A total of 104 patients were studied (55 with TA and 49 with IAA), of whom 40 (38%) were 22q11del positive. The 22q11del status was unknown in 9 (7 with TA and 2 with IAA). In patients with known deletion status, those with 22q11del had a longer hospital and intensive care length of stay. Subjects with 22q11del also required more frequent operative reintervention and more consultations and were prescribed more medications at discharge. No significant difference was found in method of feeding between those with and without 22q11del at discharge.

CONCLUSIONS

In this study, 22q11del is associated with perioperative outcomes in infants undergoing operative correction of TA and IAA, with longer hospital stays and greater resource utilization in the perioperative period. These findings should inform counseling and risk stratification and warrant additional study to identify genotype-specific management strategies to improve outcomes.

Primary immunodeficiency diagnosed at autopsy: a case report

BACKGROUND

DiGeorge syndrome may manifest as severe immunodeficiency diagnosed at infancy. The diagnosis of primary immunodeficiency is based on characteristic clinical features, immunophenotyping by flow cytometry, molecular diagnostics and functional lymphocyte evaluation. At autopsy, gross evaluation, conventional histology and immunohistochemistry may be useful for the diagnosis of primary immunodeficiency. This case report illustrates the application of autopsy and immunohistochemistry in the diagnosis of DiGeorge syndrome.

CASE PRESENTATION

A four-month-old African female infant died while undergoing treatment at Kenyatta National Hospital, a Referral and Teaching Hospital in Nairobi, Kenya. She presented with a month's history of recurrent respiratory infections, a subsequent decline in the level of consciousness and succumbed to her illness within four days. Her two older siblings died following similar circumstances at ages 3 and 5 months respectively. Autopsy revealed thymic aplasia, bronchopneumonia and invasive brain infection by Aspergillus species. Microbial cultures of cerebrospinal fluid, jejunal contents, spleen and lung tissue revealed multi drug resistant Klebsiella spp, Pseudomonas spp, Serratia spp and Escherichia coli. Immunohistochemistry of splenic tissue obtained from autopsy confirmed reduction of T lymphocytes.

CONCLUSION

Use of immunohistochemistry on histological sections of tissues derived from autopsy is a useful adjunct for post mortem diagnosis of DiGeorge syndrome.

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.

Discrepancies in parent and teacher ratings of social-behavioral functioning of children with chromosome 22q11.2 deletion syndrome: implications for assessment

Children with 22q11.2 deletion syndrome exhibit high rates of social-behavioral problems, particularly in the internalizing domain, indicating an area in need of intervention. The current investigation was designed to obtain information regarding parent and teacher ratings of the social-emotional behavior of children with 22q11DS. Using the Child Behavior Checklist (CBCL), the sample included 67 children with 22q11DS and 59 control subjects. Results indicated significant differences in social-behavioral functioning of children with 22q11DS, as compared to a control group, based on rater type. Specifically, parents reported more difficulties with internalizing problems, withdrawal, and social problems in children with 22q11DS. In contrast, teachers perceived few differences between children with 22q11DS and unaffected children. Correlational analyses indicated weak concordance between parent and teacher reports, with no significant correlations on any of three summary scales. The findings support the use of multiple methods of assessment and multiple informants when collecting information regarding the social-behavioral functioning of children with 22q11DS, and that interpretations based on only one informant/setting need to be made cautiously.

Association of IL-12p70 and IL-6:IL-10 ratio with autism-related behaviors in 22q11.2 deletion syndrome: a preliminary report

22q11.2 deletion syndrome (22q11DS) is a genetic disorder that conveys a significant risk for the development of social behavior disorders, including autism and schizophrenia. Also known as DiGeorge syndrome, 22q11DS is the second most common genetic disorder and is characterized by an elevated risk for immune dysfunction, up to 77% of individuals have an identifiable immune deficiency. We hypothesize that this immune dysfunction could contribute to the elevated risk of impaired social behavior seen in 22q11DS. The current study begins to elucidate these immune deficits and link them with the behavioral alterations associated with the disorder. Serum concentrations of a series of cytokines were examined, using a multiplex immunoassay, in sixteen individuals with 22q11DS and screened for autism-related behavior using the Autism Diagnostic Interview-Revised (ADI-R). This preliminary study examined correlations between specific immune proteins and each of the ADI-R algorithm scores (social, communication, and repetitive behavior). The inflammatory cytokine IL-1β, as well as the ratio between the inflammatory cytokine IL-6 and the anti-inflammatory cytokine IL-10, were correlated with social scores (r=0.851, p=0.004; r=0.580, p=0.018). In addition, the inflammatory cytokines interferon gamma and IL-12p70 were correlated with repetitive behaviors (r=0.795, p=0.033; r=0.774, p=0.002). Interestingly, IL-12 has been reported to be increased in autistic children. These data show a positive association between severity of autism-related behaviors and level of serum concentrations of inflammatory cytokines in individuals with 22q11DS, providing a basis for further inquiry.

A longitudinal examination of the psychoeducational, neurocognitive, and psychiatric functioning in children with 22q11.2 deletion syndrome

The present study sought to examine the longitudinal psychoeducational, neurocognitive, and psychiatric outcomes of children and adolescents with chromosome 22q11.2 deletion syndrome (22q11DS), a population with a high incidence of major psychiatric illnesses appearing in late adolescence/early adulthood. Little is known of the developmental changes that occur in the early teen years, prior to the age of highest psychosis risk. Data were collected from 71 participants (42 subjects with 22q11DS and 29 control subjects) at Time 1 (T1) and Time 2 (T2), approximately 3.5 years later. The 22q11DS group was significantly lower functioning than controls on IQ, neurocognition, and academic achievement at both T1 and T2. Children with 22q11DS also showed significantly greater social-behavioral difficulties and psychiatric symptoms, and were more likely to meet criteria for psychiatric disorders at both time points. In evaluating change over time from T1 to T2, the 22q11DS group did not show significant changes in psychoeducational or psychiatric outcomes relative to the controls, however, lack of expected age-related gains in attention regulation were noted. Within the 22q11DS group, an increase in the Attenuated Prodrome for Schizophrenia (number of psychiatric symptoms) was noted from T1 to T2 and four children with 22q11DS met criteria for Psychosis for the first time. Predictors at T1 that uncovered psychopathology symptoms at T2 included full-scale IQ, externalizing symptoms, and problem social behaviors. Overall, younger adolescent and preadolescent children with 22q11DS in this study exhibited slowed growth in attention regulation, with an increase in subclinical symptoms of schizophrenia, suggestive of increasing impairments in domains that are relevant to the high risk of Schizophrenia. Early predictors of later psychopathology included both cognitive and behavioral abnormalities. These findings begin to elucidate the trajectory of changes in psychopathology in children with 22q11DS in the years leading up to the onset of major psychiatric illnesses.

Altered development of the dorsolateral prefrontal cortex in chromosome 22q11.2 deletion syndrome: an in vivo proton spectroscopy study

BACKGROUND

Chromosome 22q11.2 deletion syndrome (22q11DS), the most common microdeletion in humans, is associated with multiple medical features, almost universal cognitive deficits, and a high risk of schizophrenia. The metabolic basis of the psychological/psychiatric features is not well understood. Volumetric brain imaging studies have shown that gray matter abnormalities in the dorsolateral prefrontal cortex (DLPFC), an area that is believed to be integral for higher neurocognition, as well as being involved in schizophrenia, are associated with the psychological manifestations. However, studies have not characterized any possible metabolite alterations within the DLPFC of children with 22q11DS and their correlations with the psychological findings.

METHODS

We conducted a short echo time, single-voxel, in vivo proton spectroscopy study involving children with 22q11DS (n = 26) and matched control subjects (n = 23).

RESULTS

Absolute N-acetylaspartate (NAA) levels from the DLPFC were significantly elevated in children with 22q11DS compared with control subjects and the elevations were associated with poor global functioning and higher rates of comorbid attention-deficit/hyperactivity disorder. Children with 22q11DS had a lack of an age-associated decrease in NAA levels, a trend seen in the control subjects. However, the results did not remain statistically significant after corrections for multiple comparisons were made.

CONCLUSIONS

These findings represent the first report of proton spectroscopy in children with 22q11DS. The elevated DLPFC NAA levels and the lack of decreasing trends in NAA with age in the 22q11DS group relative to control subjects suggest an alteration in cortical development. Also, such neuronal dysmaturation is associated with psychopathology in children with 22q11DS.

Dysregulation of DGCR6 and DGCR6L: psychopathological outcomes in chromosome 22q11.2 deletion syndrome

Chromosome 22q11.2 deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans. It is typified by highly variable symptoms, which might be explained by epigenetic regulation of genes in the interval. Using computational algorithms, our laboratory previously predicted that DiGeorge critical region 6 (DGCR6), which lies within the deletion interval, is imprinted in humans. Expression and epigenetic regulation of this gene have not, however, been examined in 22q11DS subjects. The purpose of this study was to determine if the expression levels of DGCR6 and its duplicate copy DGCR6L in 22q11DS subjects are associated with the parent-of-origin of the deletion and childhood psychopathologies. Our investigation showed no evidence of parent-of-origin-related differences in expression of both DGCR6 and DGCR6L. However, we found that the variability in DGCR6 expression was significantly greater in 22q11DS children than in age and gender-matched control individuals. Children with 22q11DS who had anxiety disorders had significantly lower DGCR6 expression, especially in subjects with the deletion on the maternal chromosome, despite the lack of imprinting. Our findings indicate that epigenetic mechanisms other than imprinting contribute to the dysregulation of these genes and the associated childhood psychopathologies observed in individuals with 22q11DS. Further studies are now needed to test the usefulness of DGCR6 and DGCR6L expression and alterations in the epigenome at these loci in predicting childhood anxiety and associated adult-onset pathologies in 22q11DS subjects.

Discordance in Diagnoses and Treatment of Psychiatric Disorders in Children and Adolescents with 22q11.2 Deletion Syndrome

This study examines the rate of utilization of mental health services in children and adolescents with 22q11DS relative to their remarkably high rate of psychiatric disorders and behavior problems. Seventy-two children and adolescents with 22q11DS were participants; their parents completed the Diagnostic Interview Schedule for Children (DISC) and the Child Behavior Checklist (CBCL). The results indicated that 22q11DS children and adolescents have higher rates of psychopathology than the general pediatric population, with ADHD and anxiety disorders being the most common. However, among youth with 22q11DS, those with psychopathology are often no more likely to receive either pharmacological or non-pharmacological mental health care than those without a given psychiatric diagnosis. Thus, although psychopathology is fairly common in this sample, many children with 22q11DS may not be receiving needed psychiatric care. These results have significant implications for these children and their families, as well as for the health care providers who treat them. In particular, the results may suggest a need for careful screening of psychiatric disorders that are likely to affect this population as well, as making appropriate treatment recommendations to remedy childhood mental health problems. Since these children face an extraordinarily high risk of psychoses in late adolescence/adulthood, treatment of childhood psychopathology could be crucial in mitigating the risk/consequences of major psychiatric illnesses in later life.

Tbx1 regulates progenitor cell proliferation in the dental epithelium by modulating Pitx2 activation of p21

Tbx1(-/-) mice present with phenotypic effects observed in DiGeorge syndrome patients however, the molecular mechanisms of Tbx1 regulating craniofacial and tooth development are unclear. Analyses of the Tbx1 null mice reveal incisor microdontia, small cervical loops and BrdU labeling reveals a defect in epithelial cell proliferation. Furthermore, Tbx1 null mice molars are lacking normal cusp morphology. Interestingly, p21 (associated with cell cycle arrest) is up regulated in the dental epithelium of Tbx1(-/-) embryos. These data suggest that Tbx1 inhibits p21 expression to allow for cell proliferation in the dental epithelial cervical loop, however Tbx1 does not directly regulate p21 expression. A new molecular mechanism has been identified where Tbx1 inhibits Pitx2 transcriptional activity and decreases the expression of Pitx2 target genes, p21, Lef-1 and Pitx2c. p21 protein is increased in PITX2C transgenic mouse embryo fibroblasts (MEF) and chromatin immunoprecipitation assays demonstrate endogenous Pitx2 binding to the p21 promoter. Tbx1 attenuates PITX2 activation of endogenous p21 expression and Tbx1 null MEFs reveal increased Pitx2a and activation of Pitx2c isoform expression. Tbx1 physically interacts with the PITX2 C-terminus and represses PITX2 transcriptional activation of the p21, LEF-1, and Pitx2c promoters. Tbx1(-/+)/Pitx2(-/+) double heterozygous mice present with an extra premolar-like tooth revealing a genetic interaction between these factors. The ability of Tbx1 to repress PITX2 activation of p21 may promote cell proliferation. In addition, PITX2 regulation of p21 reveals a new role for PITX2 in repressing cell proliferation. These data demonstrate new functional mechanisms for Tbx1 in tooth morphogenesis and provide a molecular basis for craniofacial defects in DiGeorge syndrome patients.

22q11.2 deletion syndrome: are motor deficits more than expected for IQ level?

OBJECTIVE

To examine motor function in children with 22q11.2 deletion syndrome (22q11.2) and a Full Scale IQ (FSIQ) comparable control group.

STUDY DESIGN

This study was part of a prospective study of neuropsychological function in children 9 to 15 years of age with 22q11.2 and community control subjects and included children from these two populations with comparable FSIQs.

RESULTS

Verbal IQs on the WISC-R for 40 children with 22q11.2 (88.4) and 24 community control subjects (87.2) were not different (P=.563). However, the performance IQs were (22q11.2; 81.1 vs community controls; 89.3; P<.001). On the Visual Motor Inventory, there was no difference between the standard scores of the two groups (22q11.2; 93.0 vs community control subjects; 98.1; P=.336) but on the motor coordination part of the Visual Motor Inventory, the scores of the 22q11.2 deletion syndrome group were lower (77.2 vs 89.3; P=.002). On the general neurologic examination (P=.906), the tone examination (P=.705), and the ball skills part of the Motor Battery, (P=.378), there were no differences. However, on the axial stability part of the Motor Battery, the children with 22q11.2 exhibited less good balance (P=.026).

CONCLUSIONS

School-aged children with 22q11.2 have specific motor deficits in axial stability and graphomotor skills.

DGCR8 recognizes primary transcripts of microRNAs through highly cooperative binding and formation of higher-order structures

DiGeorge critical region 8 (DGCR8) is essential for maturation of microRNAs (miRNAs) in animals. In the cleavage of primary transcripts of miRNAs (pri-miRNAs) by the Drosha nuclease, the DGCR8 protein directly binds and recognizes pri-miRNAs through a mechanism currently controversial. Our previous data suggest that DGCR8 trimerizes upon cooperative binding to pri-mir-30a. However, a separate study proposed a model in which a DGCR8 molecule contacts one or two pri-miRNA molecules using its two double-stranded RNA binding domains. Here, we extensively characterized the interaction between DGCR8 and pri-miRNAs using biochemical and structural methods. First, a strong correlation was observed between the association of DGCR8 with pri-mir-30a and the rate of pri-miRNA processing in vitro. Second, we show that the high binding cooperativity allows DGCR8 to distinguish pri-miRNAs from a nonspecific competitor with subtle differences in dissociation constants. The highly cooperative binding of DGCR8 to a pri-miRNA is mediated by the formation of higher-order structures, most likely a trimer of DGCR8 dimers, on the pri-miRNA. These properties are not limited to its interaction with pri-mir-30a. Furthermore, the amphipathic C-terminal helix of DGCR8 is important both for trimerization of DGCR8 on pri-miRNAs and for the cleavage of pri-miRNAs by Drosha. Finally, our three-dimensional model from electron tomography analysis of the negatively stained DGCR8-pri-mir-30a complex directly supports the trimerization model. Our study provides a molecular basis for recognition of pri-miRNAs by DGCR8. We further propose that the higher-order structures of the DGCR8-pri-miRNA complexes trigger the cleavage of pri-miRNAs by Drosha.

Increased incidence and size of cavum septum pellucidum in children with chromosome 22q11.2 deletion syndrome

Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a result of a hemizygotic microdeletion that results in a variety of impairments in children including greater risk for psychiatric ailments in adulthood. We used high-resolution magnetic resonance imaging to accurately quantify the length and, for the first time, volume, of the cavum septum pellucidum (CSP) in children aged 7 to 14years with 22q11.2DS and typically developing (TD) controls. Significantly greater anteroposterior length and greater CSP volumes were found in children with 22q11.2DS compared with controls. Furthermore, the largest CSP were found only in the 22q11.2DS group and with a much higher incidence than previously reported in the literature. Given the significant midline anomalies in the brains of those affected by 22q11.2DS, large CSP may be a biomarker of atypical brain development. The implication of these larger CSP for cognitive and behavioral development is a topic in need of further investigation.

DiGeorge Syndrome: a not so rare disease

INTRODUCTION

The DiGeorge Syndrome was first described in 1968 as a primary immunodeficiency resulting from the abnormal development of the third and fourth pharyngeal pouches during embryonic life. It is characterized by hypocalcemia due to hypoparathyroidism, heart defects, and thymic hypoplasia or aplasia. Its incidence is 1:3000 live births and, despite its high frequency, little is known about its natural history and progression. ←This is probably due to diagnostic difficulties and the great variety of names used to describe it, such as velocardiofacial, Shprintzen, DiGeorge, and CATCH 22 Syndromes, as well as conotruncal facial anomaly. All represent the same genetic condition, chromosome 22q11.2 deletion, which might have several clinical expressions.

OBJECTIVES

To describe clinical and laboratorial data and phenotypic characteristics of patients with DiGeorge Syndrome.

METHODS

Patients underwent standard clinical and epidemiological protocol and tests to detect heart diseases, facial abnormalities, dimorphisms, neurological or behavioral disorders, recurrent infections and other comorbidities.

RESULTS

Of 14 patients (8m - 18y11m), only one did not have 22q11.2 deletion detected. The main findings were: conotruncal malformation (n = 12), facial abnormalities (n = 11), hypocalcemia (n = 5) and low lymphocyte count (n=2).

CONCLUSION

The authors pointed out the necessity of DGS suspicion in all patient presenting with heart defects, facial abnormalities (associated or not with hypocalcemia), and immunological disorders because although frequency of DGS is high, few patients with a confirmed diagnosis are followed up.

CHARGE (coloboma, heart defect, atresia choanae, retarded growth and development, genital hypoplasia, ear anomalies/deafness) syndrome and chromosome 22q11.2 deletion syndrome: a comparison of immunologic and nonimmunologic phenotypic features

OBJECTIVES

CHARGE (coloboma, heart defect, atresia choanae, retarded growth and development, genital hypoplasia, ear anomalies/deafness) syndrome and chromosome 22q11.2 deletion syndrome are known to have significant clinical overlap including cardiac anomalies, ear abnormalities, hearing loss, developmental delay, renal abnormalities, and cleft palate. Immunodeficiency has been well documented in 22q11.2 deletion, but there has been limited recognition of this potentially serious complication in CHARGE syndrome. The goals of our study were to identify clinical features unique to CHARGE syndrome or 22q11.2 deletion and to describe the spectrum of immunodeficiency found in patients with CHARGE syndrome.

METHODS

This study included 25 children diagnosed with CHARGE syndrome with positive CHD7 mutations through the Children's Hospital of Philadelphia genetics program. Clinical features and laboratory findings were reviewed retrospectively. We compared our findings to data available for a large cohort of patients with 22q11.2 deletion syndrome followed in our clinical genetics program.

RESULTS

Features found more commonly in CHARGE syndrome included coloboma, choanal atresia, facial nerve palsy, tracheoesophageal fistula, and genital hypoplasia in boys. A high incidence of marked hypocalcemia was observed in our study group (72%). We found a spectrum of cell-mediated immunodeficiency in our study group, which ranged from lymphopenia (60%) to severe combined immunodeficiency (8%). Defects in humoral immunity were documented in 4 patients and included severe hypogammaglobulinemia with decreased T-cell numbers, transient hypogammaglobulinemia during infancy, and immunoglobulin A deficiency.

CONCLUSIONS

The presence of coloboma, choanal atresia, facial nerve palsy, tracheoesophageal fistula, or genital hypoplasia in boys should alert the clinician to the possibility of CHARGE syndrome rather than the 22q11.2 deletion. Molecular testing for CHD7 mutations may help to confirm the diagnosis. In this study, significant hypocalcemia and lymphopenia occurred more frequently in patients with CHARGE syndrome than in those with 22q11.2 deletion syndrome. Early inclusion of immunologists to the multidisciplinary care team (as with 22q11.2 deletion) may be of great benefit to affected patients.

DiGeorge syndrome presenting as late onset hypocalcaemia in adulthood

We report a 29 year old female with mild dysmorphic facial features, presenting with late onset symptomatic hypocalcaemia in adulthood. The presence of hypoparathyroidism in association with a history of transient neonatal hypocalcaemia and velopharyngeal incompetence during childhood, prompted chromosomal analysis for DiGeorge Syndrome. Fluorescence in situ hybridisation (FISH) analysis revealed a deletion of chromosome 22q11.2. This case is unusual in that the patient remained asymptomatic apart from speech and language delay after the first few months of life and presented in adulthood without any associated immunological, cardiac or renal abnormalities. The diagnosis has important implications for health and family planning.

Sclerocornea associated with the chromosome 22q11.2 deletion syndrome

Reported ocular findings in the 22q11.2 deletion syndrome (which encompasses the phenotypes of DiGeorge, velocardiofacial, and Takao (conotruncal-anomaly-face) syndromes) have included posterior embryotoxon (prominent, anteriorly displaced Schwalbe's line at the corneal limbus or edge), retinal vascular tortuosity, eyelid hooding, strabismus, and astigmatism. We present seven 22q11.2 patients from multiple centers with sclerocornea, an eye finding previously unreported in the literature. Four boys and three girls were identified with sclerocornea, systemic DGS/VCFS findings, and fluorescence in situ hybridization (FISH)-confirmed microdeletion at chromosome 22q11.2. FISH diagnosis was perinatal in six patients but at 2 years of age in one child. Sclerocornea was bilateral in five patients. Findings included descemetocele (five eyes), microophthalmos (one eye), iridocorneal adhesions (one bilateral case), and severe anterior segment dysgenesis (one eye). Two patients underwent bilateral corneal transplantation; another two were scheduled for possible unilateral transplant. Sclerocornea is a static congenital condition in which the cornea is opaque and vascularized and resembles the sclera. The novel finding of sclerocornea suggests that a genetic locus at 22q11.2 may be involved in anterior segment embryogenesis. In most of our patients, the diagnostic process was underway, but in one patient 22q11.2 deletion was not suspected until after the child had already been undergoing treatment for sclerocornea for 2 years. Sclerocornea should be added to the clinical manifestations of the 22q11.2 deletion syndrome. Ophthalmologists diagnosing sclerocornea in children with systemic findings suggestive of 22q11.2 deletion should ensure appropriate genetic referral.

Velo-cardio-facial syndrome: 30 Years of study

Velo-cardio-facial syndrome is one of the names that has been attached to one of the most common multiple anomaly syndromes in humans. The labels DiGeorge sequence, 22q11 deletion syndrome, conotruncal anomalies face syndrome, CATCH 22, and Sedlacková syndrome have all been attached to the same disorder. Velo-cardio-facial syndrome has an expansive phenotype with more than 180 clinical features described that involve essentially every organ and system. The syndrome has drawn considerable attention because a number of common psychiatric illnesses are phenotypic features including attention deficit disorder, schizophrenia, and bipolar disorder. The expression is highly variable with some individuals being essentially normal at the mildest end of the spectrum, and the most severe cases having life-threatening and life-impairing problems. The syndrome is caused by a microdeletion from chromosome 22 at the q11.2 band. Although the large majority of affected individuals have identical 3 megabase deletions, less than 10% of cases have smaller deletions of 1.5 or 2.0 megabases. The 3 megabase deletion encompasses a region containing 40 genes. The syndrome has a population prevalence of approximately 1:2,000 in the United States, although incidence is higher. Although initially a clinical diagnosis, today velo-cardio-facial syndrome can be diagnosed with extremely high accuracy by fluorescence in situ hybridization and several other laboratory techniques. Clinical management is age dependent with acute medical problems such as congenital heart disease, immune disorders, feeding problems, cleft palate, and developmental disorders occupying management in infancy and preschool years. Management shifts to cognitive, behavioral, and learning disorders during school years, and then to the potential for psychiatric disorders including psychosis in late adolescence and adult years. Although the majority of people with velo-cardio-facial syndrome do not develop psychosis, the risk for severe psychiatric illness is 25 times higher for people affected with velo-cardio-facial syndrome than that of the general population. Therefore, interest in understanding the nature of psychiatric illness in the syndrome remains strong.

Live viral vaccines in a DiGeorge syndrome patient

We report a case of pneumonia in a 13 month old male child with partial DiGeorge syndrome who died after inadvertently receiving live viral vaccines. Although live viral vaccines have been used safely in some children with DiGeorge syndrome, there are insufficient data to recommend their routine use in those with severe immunodeficiency.

Neurocognitive profile in 22q11 deletion syndrome and schizophrenia

OBJECTIVE

Schizophrenia is associated with neurocognitive deficits, but its etiologic heterogeneity may complicate the delineation of a neurocognitive profile. Schizophrenia associated with 22q11 Deletion Syndrome (22qDS) represents a more genetically homogeneous subtype for study. We hypothesized that in adults with 22qDS the neurocognitive profiles would differ between those with and without schizophrenia.

METHOD

Using a comprehensive battery of tests, we compared the neurocognitive performance profiles in those with schizophrenia (n=27; 14 M, 13 F; mean age=30.6 years, SD=7.7 years) and those with no history of psychosis (n=29; 16 M, 13 F; mean age=25.0 years, SD=9.0 years).

RESULTS

The 22qDS groups with and without schizophrenia had similar mean estimated IQ (71.6, SD=8.2 and 74.8, SD=6.1, respectively) and academic achievement, however the neurocognitive profiles of the two groups differed significantly on multivariate analysis (F(24,31)=2.25, p=0.017). The group with schizophrenia performed significantly more poorly on tests of motor skills, verbal learning, and social cognition (effect sizes>or=0.8) after correction for multiple comparisons. Other tests, but not the attentional measures used, showed nominally significant differences.

CONCLUSIONS

In adults with 22qDS, the pattern of neurocognitive differences between those with and without schizophrenia appears similar to that between patients with schizophrenia and controls. Attentional dysfunction may be a more general feature of 22qDS. The findings support 22qDS-schizophrenia as a genetic model for neurodevelopmental investigations of schizophrenia.

Olfactory disorder in children with 22q11 deletion syndrome

OBJECTIVE

22q11 deletion syndrome, a common human interstitial deletion syndrome (1:5000), is associated with a heterogeneous physical phenotype, including several factors that markedly increase the risk for olfactory disorder. Despite its potential consequences, pediatric studies of impaired olfaction are rare, and odor detection in children with 22q11 deletion syndrome has not yet been examined.

METHODS

The University of Pennsylvania Smell Identification Test was administered to 62 children, including 39 with 22q11 deletion syndrome and 23 neurotypical control siblings who ranged in age from 5.3 to 14.8 years. Lowered smell detection accuracy among affected children was predicted.

RESULTS

Substantially more children with 22q11 deletion syndrome (68%) as compared with neurotypical control subjects (13%) had University of Pennsylvania Smell Identification Test scores > or = 2 SDs below the standardization sample mean. Frequency of impairment in younger versus older children did not differ. The score distributions of children with and without velopharyngeal insufficiency did not differ; however, markedly lower score variance among children with velopharyngeal insufficiency suggested its negative impact on olfaction. Posthoc error analyses revealed that affected children had special difficulty detecting smells that are associated with fumes and smoke.

CONCLUSIONS

Odor detection failures are ubiquitous among children with 22q11 deletion syndrome and are not associated with developmental delay or performance characteristics of younger affected children. Additional studies are needed to examine further the impact on olfaction of velopharyngeal insufficiency and compromised nasal airway patency. Children with 22q11 deletion syndrome should be evaluated routinely for olfactory disorder. When deficits are identified, caregivers should be warned of potential dangers that are associated with this type of sensory impairment.

The 22q11.2 deletion in African-American patients: an underdiagnosed population?

Findings associated with the 22q11.2 deletion often include congenital heart malformations, palatal anomalies, immunodeficiency, hypocalcemia, and developmental delay or learning disabilities. Often the clinical suspicion of the diagnosis in a patient with one or more of these findings is heightened based on the presence of a characteristic facial appearance. In our large cohort of 370 patients with the 22q11.2 deletion, we report the under-representation of African-Americans in our group, as well as, the paucity of craniofacial dysmorphism in these patients. We note that the absence of the typical facial features may result in decreased ascertainment in this population and, furthermore, may delay the implementation of palliative care, cognitive remediation, and recurrence risk counseling. We, therefore, suggest that the clinician's threshold of suspicion should be lower in African-American patients.

Postmaturity in a genetic subtype of schizophrenia

OBJECTIVE

To determine whether postmaturity (gestation > 41 weeks), small for gestational age (SGA), and other pregnancy and birth complications that may elevate risk for neurodevelopmental disorders, are associated with elevated risk for schizophrenia in 22q11 Deletion Syndrome (22qDS), a genetic subtype of schizophrenia.

METHOD

Antepartum and intrapartum features were examined in 20 adults with 22qDS-schizophrenia and three comparison groups: newborn encephalopathy (n = 164) and healthy newborn controls (n = 400) from Badawi et al.'s (Br Med J 1998, 317: 1549) study, and 16 non-psychotic 22qDS adults (22qDS-NP).

RESULTS

Postmaturity (OR 13.0, 95% CI 3.95, 42.77; P < 0.001) and SGA (OR 3.59, 95% CI 1.23, 10.5; P = 0.03) were more prevalent in 22qDS-SZ than controls. Postmaturity was non-significantly more prevalent in 22qDS-SZ than in newborn encephalopathy (P = 0.06) or 22qDS-NP (P = 0.2). SGA showed similar rates in the two 22qDS groups and newborn encephalopathy, but was more prevalent in 22qDS-NP than controls (P = 0.05).

CONCLUSION

The results suggest that postmaturity may be associated with expression of schizophrenia in a 22qDS subtype of schizophrenia. SGA may be a non-specific marker of neurodevelopmental disturbance.

Tbx1 is regulated by tissue-specific forkhead proteins through a common Sonic hedgehog-responsive enhancer

Haploinsufficiency of Tbx1 is likely a major determinant of cardiac and craniofacial birth defects associated with DiGeorge syndrome. Although mice deficient in Tbx1 exhibit pharyngeal and aortic arch defects, the developmental program and mechanisms through which Tbx1 functions are relatively unknown. We identified a single cis-element upstream of Tbx1 that recognized winged helix/forkhead box (Fox)-containing transcription factors and was essential for regulation of Tbx1 transcription in the pharyngeal endoderm and head mesenchyme. The Tbx1 regulatory region was responsive to signaling by Sonic hedgehog (Shh) in vivo. We show that Shh is necessary for aortic arch development, similar to Tbx1, and is also required for expression of Foxa2 and Foxc2 in the pharyngeal endoderm and head mesenchyme, respectively. Foxa2, Foxc1, or Foxc2 could bind and activate transcription through the critical cis-element upstream of Tbx1, and Foxc proteins were required, within their expression domains, for Tbx1 transcription in vivo. We propose that Tbx1 is a direct transcriptional target of Fox proteins and that Fox proteins may serve an intermediary role in Shh regulation of Tbx1.

T cell receptor repertoire and function in patients with DiGeorge syndrome and velocardiofacial syndrome

DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS) are associated with chromosome 22q11.2 deletion. Limited information is available on the T cell receptor (TCR) Vbeta repertoire. We therefore investigated TCR Vbeta families in lymphocytes isolated from blood and thymic samples of seven patients with DGS and seven patients with VCFS, all with 22q11.2 deletion. We also studied activities related to TCR signalling including in vitro proliferation, anti-CD3-induced protein tyrosine phosphorylation, and susceptibility to apoptosis. Reduced CD3+ T cells were observed in most patients. Spontaneous improvement of T cell numbers was detected in patients, 3 years after the first study. Analysis of CD4+ and CD8+ TCR Vbeta repertoire in peripheral and thymic cells showed a normal distribution of populations even if occasional deletions were observed. Lymphoproliferative responses to mitogens were comparable to controls as well as anti-CD3-induced protein tyrosine phosphorylation. Increased anti-CD3-mediated apoptosis was observed in thymic cells. Our data support the idea that in patients surviving the correction of cardiac anomalies, the immune defect appears milder than originally thought, suggesting development of a normal repertoire of mature T cells.

Increased spontaneous apoptosis in T lymphocytes in DiGeorge anomaly

The aim of this study was to determine whether increased apoptosis in peripheral blood lymphocytes plays a role in T cell deficiency associated with DiGeorge anomaly. T cell subsets from a patient with DiGeorge anomaly were examined for the expression of Fas, FasL, Bcl-2 and Bcl-XL at the protein level with monoclonal antibodies, using dual-colour flow cytometry, and at the mRNA level in mononuclear cells by quantitative reverse transcriptase-polymerase chain reaction. In vitro spontaneous apoptosis was examined by propidium iodide staining and DNA fragmentation, using flow cytometry and gel electrophoresis, respectively. Fas and FasL expression, both at the level of protein and of mRNA, was increased, whereas Bcl-2 expression was decreased both at the level of protein and of mRNA. However, no difference in Bcl-XL expression was observed between the patient and an age-matched control. A significant proportion of both CD4+ and CD8+ T cells from the patients underwent spontaneous apoptosis, whereas almost no spontaneous apoptosis was observed in the age-matched control. These data suggest that spontaneous apoptosis in T lymphocytes, at least in part, may be responsible for T cell deficiency in DiGeorge anomaly.

Truncus arteriosus and double aortic arch associated with DiGeorge syndrome

We report the 1st known case in which truncus arteriosus and double aortic arch have been associated with DiGeorge syndrome. The association of these 2 cardiovascular anomalies lends support, by itself, to speculation that truncus arteriosus and double aortic arch have a common embryonic pathogenesis; and the presence of these anomalies in a patient with DiGeorge syndrome strengthens the contention that the common causative factor is pathologic development of the neural crest cells.