Microcystic lymphatic malformations in Turner syndrome are due to somatic mosaicism of PIK3CA.

Turner syndrome (45,X) is caused by a complete or partial absence of a single X chromosome. Vascular malformations occur due to abnormal development of blood and/or lymphatic vessels. They arise from either somatic or germline pathogenic variants in the genes regulating growth and apoptosis of vascular channels. Aortic abnormalities are a common, known vascular anomaly of Turner syndrome. However, previous studies have described other vascular malformations as a rare feature of Turner syndrome and suggested that vascular abnormalities in individuals with Turner syndrome may be more generalized. In this study, we describe two individuals with co-occurrence of Turner syndrome and vascular malformations with a lymphatic component. In these individuals, genetic testing of the lesional tissue revealed a somatic pathogenic variant in PIK3CA-a known and common cause of lymphatic malformations. Based on this finding, we conclude that the vascular malformations presented here and likely those previously in the literature are not a rare part of the clinical spectrum of Turner syndrome, but rather a separate clinical entity that may or may not co-occur in individuals with Turner syndrome.

Prenatal vs postnatal diagnosis of 22q11.2 deletion syndrome: cardiac and noncardiac outcomes through 1 year of age.

BACKGROUND: The 22q11.2 deletion syndrome is the most common microdeletion syndrome and is frequently associated with congenital heart disease. Prenatal diagnosis of 22q11.2 deletion syndrome is increasingly offered. It is unknown whether there is a clinical benefit to prenatal detection as compared with postnatal diagnosis. OBJECTIVE: This study aimed to determine differences in perinatal and infant outcomes between patients with prenatal and postnatal diagnosis of 22q11.2 deletion syndrome. STUDY DESIGN: This was a retrospective cohort study across multiple international centers (30 sites, 4 continents) from 2006 to 2019. Participants were fetuses, neonates, or infants with a genetic diagnosis of 22q11.2 deletion syndrome by 1 year of age with or without congenital heart disease; those with prenatal diagnosis or suspicion (suggestive ultrasound findings and/or high-risk cell-free fetal DNA screen for 22q11.2 deletion syndrome with postnatal confirmation) were compared with those with postnatal diagnosis. Perinatal management, cardiac and noncardiac morbidity, and mortality by 1 year were assessed. Outcomes were adjusted for presence of critical congenital heart disease, gestational age at birth, and site. RESULTS: A total of 625 fetuses, neonates, or infants with 22q11.2 deletion syndrome (53.4% male) were included: 259 fetuses were prenatally diagnosed (156 [60.2%] were live-born) and 122 neonates were prenatally suspected with postnatal confirmation, whereas 244 infants were postnatally diagnosed. In the live-born cohort (n=522), 1-year mortality was 5.9%, which did not differ between groups but differed by the presence of critical congenital heart disease (hazard ratio, 4.18; 95% confidence interval, 1.56-11.18; P<.001) and gestational age at birth (hazard ratio, 0.78 per week; 95% confidence interval, 0.69-0.89; P<.001). Adjusting for critical congenital heart disease and gestational age at birth, the prenatal cohort was less likely to deliver at a local community hospital (5.1% vs 38.2%; odds ratio, 0.11; 95% confidence interval, 0.06-0.23; P<.001), experience neonatal cardiac decompensation (1.3% vs 5.0%; odds ratio, 0.11; 95% confidence interval, 0.03-0.49; P=.004), or have failure to thrive by 1 year (43.4% vs 50.3%; odds ratio, 0.58; 95% confidence interval, 0.36-0.91; P=.019). CONCLUSION: Prenatal detection of 22q11.2 deletion syndrome was associated with improved delivery management and less cardiac and noncardiac morbidity, but not mortality, compared with postnatal detection.

A case-control study of bleeding risk in children with 22q11.2 deletion syndrome undergoing cardiac surgery.

Previous research suggests that individuals with 22q11.2 deletion syndrome (DS) have an increased risk of bleeding following cardiac surgery. However, current guidelines for management of patients with 22q11.2DS do not provide specific recommendations for perioperative management. This study sought to identify specific risk factors for bleeding in this patient population. Examine the factors determining bleeding and transfusion requirements in patients with 22q11.2DS undergoing cardiac surgery. This was a single center review of patients who underwent cardiac surgery at the Children's Hospital of Philadelphia from 2000 to 2016. Data was extracted from the medical record. Frequency of bleeding events, laboratory values, and transfusion requirements were compared. We included 226 patients with 22q11.2DS and 506 controls. Bleeding events were identified in 13 patients with 22q11.2DS (5.8%) and 27 controls (5.3%). Platelet counts were lower among patients with 22q11.2DS than in control patients, but not statistically different comparing bleeding to not bleeding. Patients with 22q11.2DS received more transfusions (regardless of bleeding status). However, multivariate analysis showed only procedure type was associated with increased risk of bleeding (p = .012). The overall risk of bleeding when undergoing cardiac surgery is not different in patients with 22q11.2DS compared to non-deleted patients. Though platelet counts were lower in patients with 22q11.2DS, only procedure type was significantly associated with an increased risk of bleeding.

Complete Sequence of the 22q11.2 Allele in 1,053 Subjects with 22q11.2 Deletion Syndrome Reveals Modifiers of Conotruncal Heart Defects.

The 22q11.2 deletion syndrome (22q11.2DS) results from non-allelic homologous recombination between low-copy repeats termed LCR22. About 60%-70% of individuals with the typical 3 megabase (Mb) deletion from LCR22A-D have congenital heart disease, mostly of the conotruncal type (CTD), whereas others have normal cardiac anatomy. In this study, we tested whether variants in the hemizygous LCR22A-D region are associated with risk for CTDs on the basis of the sequence of the 22q11.2 region from 1,053 22q11.2DS individuals. We found a significant association (FDR p < 0.05) of the CTD subset with 62 common variants in a single linkage disequilibrium (LD) block in a 350 kb interval harboring CRKL. A total of 45 of the 62 variants were associated with increased risk for CTDs (odds ratio [OR) ranges: 1.64-4.75). Associations of four variants were replicated in a meta-analysis of three genome-wide association studies of CTDs in affected individuals without 22q11.2DS. One of the replicated variants, rs178252, is located in an open chromatin region and resides in the double-elite enhancer, GH22J020947, that is predicted to regulate CRKL (CRK-like proto-oncogene, cytoplasmic adaptor) expression. Approximately 23% of patients with nested LCR22C-D deletions have CTDs, and inactivation of Crkl in mice causes CTDs, thus implicating this gene as a modifier. Rs178252 and rs6004160 are expression quantitative trait loci (eQTLs) of CRKL. Furthermore, set-based tests identified an enhancer that is predicted to target CRKL and is significantly associated with CTD risk (GH22J020946, sequence kernal association test (SKAT) p = 7.21 × 10-5) in the 22q11.2DS cohort. These findings suggest that variance in CTD penetrance in the 22q11.2DS population can be explained in part by variants affecting CRKL expression.

Immunologic, Molecular, and Clinical Profile of Patients with Chromosome 22q11.2 Duplications.

PURPOSE: Duplication of chromosome 22q11.2 due to meiotic non-allelic homologous recombination results in a distinct syndrome, chromosome 22q11.2 duplication syndrome that has some overlapping phenotypic features with the corresponding 22q11.2 deletion syndrome. Literature on immunologic aspects of the duplication syndrome is limited. We conducted a retrospective study of 216 patients with this syndrome to better define the key features of the duplication syndrome. METHODS: Single-center retrospective record review was performed. Data regarding demographics, clinical details, and immunological tests were compiled, extracted into a predetermined data collection form, and analyzed. RESULTS: This cohort comprised 113 (52.3%) males and 103 (47.7%) females. The majority (54.6%) of mapped duplications were between low copy repeat regions A-D (LCR22A to -D). Though T cell subsets were relatively preserved, switched memory B cells, immunoglobulins, and specific antibodies were each found to be decreased in a subset of the cohort. One-fifth (17/79, 21.5%) of patients had at least 2 low immunoglobulin values, and panhypogammaglobulinemia was found in 11.7% (9/79) cases. Four children were on regular immunoglobulin replacement therapy. Asthma and eczema were the predominant atopic symptoms in our cohort. CONCLUSION: Significant immunodeficiencies were observed in our cohort, particularly in B cells and antibodies. Our study expands the current clinical understanding and emphasizes the need of immunological studies and multidisciplinary approaches for these patients.

Platelet findings in 22q11.2 deletion syndrome correlate with disease manifestations but do not correlate with GPIb surface expression.

Prior studies have demonstrated that patients with chromosome 22q11.2 deletion syndrome (22q11.2DS) have lower platelet counts (PC) compared to non-deleted populations. They also have an increased mean platelet volume. The mechanism for this has been postulated to be haploinsufficiency of the GPIBB gene. We examined platelet parameters, deletion size and factors known to influence counts, including status of thyroid hormone and congenital heart disease (CHD), in a population of 825 patients with 22q11.2DS. We also measured surface expression of GPIB-IX complex by flow cytometry. The major determinant of PC was deletion status of GP1BB, regardless of surface expression or other factors. Patients with nested distal chromosome 22q11.2 deletions (those with GP1BB present) had higher PCs than those with proximal deletions where GP1BB is deleted. Patients with 22q11.2DS also demonstrated an accelerated PC decrease with age, occurring in childhood. These data demonstrate that genes within the proximal deletion segment drive PC differences in 22q11.2DS and suggest that PC reference ranges may need to be adjusted for age and deletion size in 22q11.2DS populations. Bleeding did not correlate with either platelet count or GPIb expression. Further studies into drivers of expression of GPIb and associations with severe thrombocytopenia and immune thrombocytopenia are needed to inform clinical care.

Psychosis spectrum features, neurocognition and functioning in a longitudinal study of youth with 22q11.2 deletion syndrome.

BACKGROUND: Neuropsychiatric disorders are common in 22q11.2 Deletion Syndrome (22q11DS) with about 25% of affected individuals developing schizophrenia spectrum disorders by young adulthood. Longitudinal evaluation of psychosis spectrum features and neurocognition can establish developmental trajectories and impact on functional outcome. METHODS: 157 youth with 22q11DS were assessed longitudinally for psychopathology focusing on psychosis spectrum symptoms, neurocognitive performance and global functioning. We contrasted the pattern of positive and negative psychosis spectrum symptoms and neurocognitive performance differentiating those with more prominent Psychosis Spectrum symptoms (PS+) to those without prominent psychosis symptoms (PS-). RESULTS: We identified differences in the trajectories of psychosis symptoms and neurocognitive performance between the groups. The PS+ group showed age associated increase in symptom severity, especially negative symptoms and general nonspecific symptoms. Correspondingly, their level of functioning was worse and deteriorated more steeply than the PS- group. Neurocognitive performance was generally comparable in PS+ and PS- groups and demonstrated a similar age-related trajectory. However, worsening executive functioning distinguished the PS+ group from PS- counterparts. Notably, of the three executive function measures examined, only working memory showed a significant difference between the groups in rate of change. Finally, structural equation modeling showed that neurocognitive decline drove the clinical change. CONCLUSIONS: Youth with 22q11DS and more prominent psychosis features show worsening of symptoms and functional decline driven by neurocognitive decline, most related to executive functions and specifically working memory. The results underscore the importance of working memory in the developmental progression of psychosis.

Distinct immune trajectories in patients with chromosome 22q11.2 deletion syndrome and immune-mediated diseases.

BACKGROUND: Identification of biomarkers associated with immune-mediated diseases in 22q11.2 deletion syndrome is an evolving field. OBJECTIVES: We sought to use a carefully phenotyped cohort to study immune parameters associated with autoimmunity and atopy in 22q11.2 deletion syndrome to define biomarkers associated with immune-mediated disease in this syndrome. METHODS: Chart review validated autoimmune disease and atopic condition diagnoses. Laboratory data were extracted for each subcohort and plotted according to age. A random-effects model was used to define statistical significance. RESULTS: CD19, CD4, and CD4/45RA lymphocyte populations were not different from the general cohort for patients with atopic conditions. CD4/45RA T cells were significantly lower in the subjects with immune thrombocytopenia compared with the general cohort, and CD4 T-cell counts were lower in patients with autoimmune thyroid disease. CONCLUSIONS: The mechanisms of autoimmunity in cytopenias may be distinct from those of solid-organ autoimmunity in 22q11.2 deletion syndrome. This study identifies potential biomarkers for risk stratification among commonly obtained laboratory studies.

The experience of one pediatric geneticist with telemedicine-based clinical diagnosis.

Telemedicine has long been considered as an attractive alternative methodology in clinical genetics to improve patient access and convenience. Given the importance of the dysmorphology physical examination and anthropometric measurement in clinical genetics, many have wondered if lost information would hamper diagnosis. We previously addressed this question by analyzing thousands of diagnostic encounters in a single practice involving multiple practitioners and found no evidence for a difference in new molecular diagnosis rates. However, our previous study design resulted in variability in providers between in-person and telemedicine evaluation groups. To address this in our present study, we expanded our analysis to 1104 new patient evaluations seen by one highly experienced clinical geneticist across two 10-month periods before and after the start of the COVID-19 pandemic. Comparing patients seen in-person to those seen by telemedicine, we found significant differences in race and ethnicity, preferred language, and home zip code median income. The clinical geneticist intended to send more genetic testing for those patients seen by telemedicine, but due to issues with test authorization and sample collection, there was no difference in ultimate completion rate between groups. We found no significant difference in new molecular diagnosis rate. Overall, we find telemedicine to be an acceptable alternative to in-person evaluation for routine pediatric clinical genetics care.

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.

Chromosome 22q11 copy number variants and single ventricle CHD.

OBJECTIVES: CHD is an important phenotypic feature of chromosome 22q11.2 copy number variants. Biventricular repair is usually possible, however there are rare reports of patients with chromosome 22q copy number variants and functional single ventricle cardiac disease. METHODS: This is a single centre retrospective review of patients with chromosome 22q copy number variants who underwent staged single ventricle reconstructive surgery between 1 July, 1984 and 31 December, 2020. RESULTS: Seventeen patients met inclusion criteria. The most common diagnosis was hypoplastic left heart syndrome (n = 8) and vascular anomalies were present in 13 patients. A microdeletion of the chromosome 22 A-D low-copy repeat was present in 13 patients, and the remaining had a duplication. About half of the patients had documented craniofacial abnormalities and/or hypocalcaemia, and developmental delay was very common. Fifteen patients had a Norwood operation, 10 patients had a superior cavopulmonary anastomosis, and 7 patients had a Fontan. Two patients had cardiac transplantation after Fontan. Overall survival is 64% at 1 year, and 58% at 5 and 10 years. Most deaths occurred following Norwood operation (n = 5). CONCLUSIONS: CHD necessitating single ventricle reconstruction associated with chromosome 22q copy number variants is not common, but typically occurs as a variant of hypoplastic left heart syndrome with the usual cytogenetic microdeletion. The most common neonatal surgical intervention performed is the Norwood, where most of the mortality burden occurs. Associated anomalies and medical issues may cause additional morbidity after cardiac surgery, but survival is similar to infants with other types of single ventricle disease.

Surgical insights and management in patients with the 22q11.2 deletion syndrome.

PURPOSE: 22q11.2 deletion syndrome (22q11.2DS) can present with a variety challenges to patients and their caregivers, many of which require surgical evaluation and intervention. Surgical needs can also extend long into adulthood, prompting evaluation and intervention throughout development and beyond. Here, we identify common concerns and patient needs associated with the 22q11.2DS from a general surgery perspective, their management, and typical management based on our institution's experience with 1263 patients. METHODS: 1263 patients evaluated and treated at the 22q And You Center at the Children's Hospital of Philadelphia were enrolled and included in the study, from January 1992 to May 2017 Co-morbidities, procedures, and imaging studies performed were quantified and assessed via descriptive analysis. RESULTS: Gastroesophageal reflux disease (GERD) and feeding difficulties were the most common surgical issues identified, while gastrostomy tube placement, anorectal procedures, and hernia repairs were the most common surgical interventions performed by general surgeons. CONCLUSIONS: General surgical procedures are commonly needed in this population and are part of the complex needs these patients and their surgeons may encounter in the setting of a 22q11.2DS diagnosis. These findings will help to inform a well-coordinated, multidisciplinary approach to care.

Chromatin Modifications in 22q11.2 Deletion Syndrome.

PURPOSE: Chromosome 22q11.2 deletion syndrome is a common inborn error of immunity. The early consequences of thymic hypoplasia are low T cell numbers. Later in life, atopy, autoimmunity, inflammation, and evolving hypogammaglobulinemia can occur and the causes of these features are not understood. This study utilized an unbiased discovery approach to define alterations in histone modifications. Our goal was to identify durable chromatin changes that could influence cell behavior. METHODS: CD4 T cells and CD19 B cells underwent ChIP-seq analysis using antibodies to H3K4me3, H3K27ac, and H4ac. RNA effects were defined in CD4 T cells by RNA-seq. Serum cytokines were examined by Luminex. RESULTS: Histone marks of transcriptional activation at CD4 T cell promoters and enhancers were globally increased. The promoter activation signature had elements related to T cell activation and inflammation, concordant with effects seen in the transcriptome. B cells, in contrast, had a minimally altered epigenetic landscape in 22q11.2. Both cell types had an "edge" effect with markedly altered chromatin adjacent to the deletion. CONCLUSIONS: People with 22q11.2 deletion have altered CD4 T cell chromatin and a transcriptome concordant with the changes in the epigenome. These effects support a disease model where qualitative changes to T cells occur in addition to quantitative defects that have been well characterized. This study offers unique insight into qualitative differences in the T cells in 22q11.2 deletion, an aspect that has received limited attention.

Cardiac evaluation of patients with 22q11.2 duplication syndrome.

The 22q11.2 duplication syndrome (22q11.2DupS) is characterized by phenotypic heterogeneity, from seemingly asymptomatic to severely affected patients. Our study sought to detail the cardiac phenotype associated with 22q11.2DupS, the prevalence of aortic arch anomalies and aortic root dilation in 22q11.2DupS, and to assess how frequently new congenital heart disease (CHD) is diagnosed at outpatient cardiac evaluation following genetic diagnosis. In our cohort of 85 patients, 20.0% had CHD, with a wide range of phenotypes. Sixty-eight patients had complete cardiac evaluations detailing aortic arch sidedness and branching pattern, of which 5 (7.4%) had an aortic arch anomaly, all of whom had concurrent intracardiac CHD. Of 53 patients without CHD who had complete cardiac evaluations, only 3 (5.7%) had evidence of aortic root dilation. Of 46 patients who underwent outpatient cardiac evaluation following diagnosis of 22q11.2DupS, only one (2.2%) was found to have CHD, an isolated bicuspid aortic valve without stenosis. Therefore, the CHD phenotype in 22q11.2DupS, when present, is heterogeneous. Aortic arch anomalies are uncommon, and no patient in our cohort had one in isolation. Isolated aortic root dilation is also uncommon. Finally, outpatient cardiac evaluation following genetic diagnosis without previously known CHD infrequently identified minor cardiac malformations.

Aortic Root Dilation in Patients with 22q11.2 Deletion Syndrome Without Intracardiac Anomalies.

Aortic root dilation (ARD) has been reported in patients with 22q11.2 deletion syndrome (22q11.2DS) with and without congenital heart defects (CHDs). However, the long-term implications of isolated ARD in 22q11.2DS remain undefined. In this study, we measured aortic root size and estimated the probability of changing between normal aortic root size and ARD during follow up to understand the prevalence, longitudinal course, and clinical risk factors for ARD in patients with 22q11.2DS without intracardiac CHDs. Aortic root size was measured in 251 patients with 432 studies. Forty-one patients (16.3%) had ARD on at least one echocardiogram and the cohort sinus Z-score was increased on the last echocardiogram [mean (1.09, SD 1.24) and median (1.20, min - 1.90 and max 5.40)]. Transition probability analysis showed that 8.1% of patients developed ARD and 45.4% of patients with ARD reverted to normal at the next echocardiogram. The risk of ARD over time was significantly associated with male sex (OR 3.06, 95% CI 1.41-6.65; p = 0.004), but not with age or presence of an aortic arch anomaly. Compared to a sinus Z-score ≥ 2, initial Z-score < 2 was associated with 14.3 times lower risk of developing sinus Z-score ≥ 3 at follow up. Sinus Z-score overall decreased by age, and males had a higher Z-score than females (ß = 0.72, SE = 0.14, p < 0.001). Though only a few patients had a Z-score > 4, and patients with initial Z-scores < 2 seem unlikely to develop clinically significant disease, screening practices remain incompletely defined such that periodic evaluation appears warranted.

Pathogenic variants in CDC45 on the remaining allele in patients with a chromosome 22q11.2 deletion result in a novel autosomal recessive condition.

PURPOSE: The 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion in humans, with highly variable phenotypic expression. Whereas congenital heart defects, palatal anomalies, immunodeficiency, hypoparathyroidism, and neuropsychiatric conditions are observed in over 50% of patients with 22q11DS, a subset of patients present with additional "atypical" findings such as craniosynostosis and anorectal malformations. Recently, pathogenic variants in the CDC45 (Cell Division Cycle protein 45) gene, located within the LCR22A-LCR22B region of chromosome 22q11.2, were noted to be involved in the pathogenesis of craniosynostosis. METHODS: We performed next-generation sequencing on DNA from 15 patients with 22q11.2DS and atypical phenotypic features such as craniosynostosis, short stature, skeletal differences, and anorectal malformations. RESULTS: We identified four novel rare nonsynonymous variants in CDC45 in 5/15 patients with 22q11.2DS and craniosynostosis and/or other atypical findings. CONCLUSION: This study supports CDC45 as a causative gene in craniosynostosis, as well as a number of other anomalies. We suggest that this association results in a condition independent of Meier-Gorlin syndrome, perhaps representing a novel condition and/or a cause of features associated with Baller-Gerold syndrome. In addition, this work confirms that the phenotypic variability observed in a subset of patients with 22q11.2DS is due to pathogenic variants on the nondeleted chromosome.

Palatal evaluation and treatment in 22q11.2 deletion syndrome.

Palatal involvement occurs commonly in patients with 22q11.2 Deletion Syndrome (22qDS), and includes palatal clefting and velopharyngeal dysfunction in the absence of overt or submucous clefts. The reported incidence and distribution of palatal abnormalities vary in the literature. The aim of this article is to revisit the incidence and presenting features of palatal abnormalities in a large cohort of patients with 22qDS, summarize the surgical treatments performed in this cohort, and provide an overview of surgical treatment protocols and management guidelines for palatal abnormalities in this syndrome. Charts of 1,121 patients seen through the 22q and You Center at the Children's Hospital of Philadelphia were reviewed for palatal status, demographic factors, deletion size, and corrective surgical procedures. Statistical analysis was performed using Pearson's chi-squared test to identify differences between gender, deletion size, and palatal abnormality. Of the patients with complete evaluations, 67% were found to have a palatal abnormality. The most common finding was velopharyngeal dysfunction in 55.2% of patients, and in 33.3% of patients, this occurred in the absence of palatal clefting. There was no significant difference in the incidence of palatal abnormalities by gender; however, a difference was noted among race (p < 0.01) and deletion sizes (p < 0.01). For example, Caucasian and Asian patients presented with a much higher prevalence of palatal abnormalities, and conversely those with nested deletions presented with a much lower rate of palatal defects. Overall, 26.9% of patients underwent palatal surgery, and the most common indication was velopharyngeal dysfunction. Palatal abnormalities are a hallmark feature of 22q11.2 Deletion Syndrome; understanding the incidence, presenting features, and treatment protocols are essential for practitioners counseling and treating families affected with this disorder.

The impact of hypocalcemia on full scale IQ in patients with 22q11.2 deletion syndrome.

Hypocalcemia has been reported in ~50% of patients 22q11.2DS and calcium regulation is known to play a role in neuronal development and synaptic plasticity. Because calcium ions play a role in neuronal function and development, we hypothesized that hypocalcemia would be associated with adverse effects on full scale IQ index (FSIQ) in patients with 22q11.2DS. A retrospective chart review cataloguing the presence or absence of hypocalcemia in 1073 subjects with a laboratory confirmed chromosome 22q11.2 deletion evaluated at the Children's Hospital of Philadelphia was conducted. 852/1073 patients had an endocrinology evaluation with laboratory confirmed calcium levels. 466/852 (54.7%) had a diagnosis of hypocalcemia. 265/1073 subjects ranging from 0 to 51 years of age had both calcium levels measured and a neuropsychological evaluation yielding a FSIQ. The mean FSIQ for 146/265 patients with hypocalcemia was 77.09 (SD = 13.56) and the mean FSIQ for 119/265 patients with normocalcemia was 77.27 (SD = 14.25). The distribution of patients with intellectual disability (ID) (FSIQ<69), borderline IQ (FSIQ 70-79), and average IQ (FSIQ>80) between the hypocalcemic and normocalcemic groups was not statistically significant (χ2 = 0.2676, p = 0.8748). Neonatal hypocalcemic seizures were not found to be associated with ID. We found no difference in FSIQ between the hypocalcemic and non-hypocalcemic patients with 22q11.2DS. As our findings differ from a previous report in adult subjects, we speculate that this may reflect a potential benefit from early treatment of hypocalcemia and may support early 22q11.2 deletion detection in order to offer prompt diagnosis and subsequent treatment of hypocalcemia.

Elucidating the diagnostic odyssey of 22q11.2 deletion syndrome.

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

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

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