22q11 deletion syndrome: current perspective

In-silico identification of deleterious non-synonymous SNPs of TBX1 gene: Functional and structural impact towards 22q11.2DS

The TBX1 gene plays a critical role in the development of 22q11.2 deletion syndrome (22q11.2DS), a complex genetic disorder associated with various phenotypic manifestations. In this study, we performed in-silico analysis to identify potentially deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) within the TBX1 gene and evaluate their functional and structural impact on 22q11.2DS. A comprehensive analysis pipeline involving multiple computational tools was employed to predict the pathogenicity of nsSNPs. This study assessed protein stability and explored potential alterations in protein-protein interactions. The results revealed the rs751339103(C>A), rs780800634(G>A), rs1936727304(T>C), rs1223320618(G>A), rs1248532217(T>C), rs1294927055 (C>T), rs1331240435 (A>G, rs1601289406 (A>C), rs1936726164 (G>A), and rs911796187(G>A) with a high-risk potential for affecting protein function and stability. These nsSNPs were further analyzed for their impact on post-translational modifications and structural characteristics, indicating their potential disruption of molecular pathways associated with TBX1 and its interacting partners. These findings provide a foundation for further experimental studies and elucidation of potential therapeutic targets and personalized treatment approaches for individuals affected by 22q11.2DS.

Otorhinologic Disorders in 22q11.2 Deletion Syndrome

OBJECTIVE

Investigate incidence and natural history of otologic and sinonasal disease associated with 22q11.2 deletion syndrome.

STUDY DESIGN

Case series.

SETTING

Tertiary care children's hospital.

METHODS

Charts from consecutive children born 2000 to 2018 with a diagnosis of 22q11.2 deletion, DiGeorge, or velocardiofacial syndrome based on the International Classification of Diseases (ICD)-9 and ICD-10 codes were reviewed. Otologic and rhinologic diagnoses and surgeries and immune and microbiologic laboratory findings were collected from the medical record.

RESULTS

After the exclusion of patients with no 22q11.2 deletion (n = 101), otologic care at an outside hospital (n = 59), and loss to follow-up prior to 3 years of age (n = 22), 128 were included. Males comprised 80 (62.5%) patients, 115 (89.8%) were white, and the median age at genetic confirmation of 22q11.2 deletion was 119 days (range 0 days to 14.6 years). Recurrent acute otitis media (RAOM), chronic otitis media with effusion, chronic rhinosinusitis, and recurrent acute sinusitis were diagnosed in 54 (42.2%), 37 (28.9%), 10 (7.8%), and 8 (6.3%), respectively. Tympanostomy tubes were placed in 49 (38.3%). Adenoidectomy and sinus surgery were performed in 38 (29.7%) and 4 (3.1%), respectively. Neither immunoglobulin nor cluster of differentiation deficiency increased the odds of RAOM diagnosis, tympanostomy tube placement, or chronic/recurrent sinusitis. Methicillin-resistant Staphylococcus aureus was the most common organism in sinus cultures (4/13, 30.8%). Streptococcus pneumonia dominated otorrhea cultures (11/21, 52.4%).

CONCLUSION

Approximately half of children with 22q11.2 deletion may experience otologic disease that often requires surgical management. Future studies will utilize a larger cohort to examine the role of immunodeficiency in otologic and rhinologic disease in this population.

Description of Neuropsychological Profile in Patients with 22q11 Syndrome

BACKGROUND

22q11 deletion syndrome (SD22Q11) is a neurogenetic condition that is associated with a high risk of neurodevelopmental disorders and intellectual disability. People with SD22Q11, both children and adults, often experience significant difficulties in social interactions, as well as neurocognitive deficits, and have elevated rates of autism spectrum disorder (ASD). Despite this, the relationship between basic cognitive processes and cognitive ability in this population has not been well investigated.

METHODS

the main objective of the present research is to describe the neurocognitive profile of people with SD22Q11 using standardized neuropsychological assessment instruments. For this purpose, a sample of 10 participants aged between 7 and 15 years was administered an assessment battery with the following tests: WISC-V, CELF-5, NEPSY-II, CSAT-R, CARAS-R, TP, MABC-2, BRIEF-2, SENA, DABAS, ABAS-II, SCQ, and ADOS-2.

RESULTS

the results showed IQ scores in the borderline normal range, as well as difficulties in language functions, social skills, motor skills, and executive functions.

CONCLUSIONS

an individualized assessment taking into account the globality of its expression, and a therapeutic approach adapted to the specific needs of children with this syndrome is essential.

Endocrine Abnormalities and Growth Characterization in Colombian Pediatric Patients with 22q11 Deletion Syndrome

OBJECTIVE

Several endocrine manifestations have been described in patients with 22q11 deletion syndrome, including growth retardation, hypoparathyroidism, and thyroid disorders. This study aimed to characterize these abnormalities in a Colombian retrospective cohort of children with this condition.

METHODS

A retrospective study comprising a cohort of children with 22q11 deletion syndrome in Medellín, Colombia followed up between 2011 and 2017 was conducted.

RESULTS

Thirty-seven patients with a confirmed diagnosis of 22q11 deletion syndrome were included. 37.8% had some endocrinopathy, the most frequent being hypoparathyroidism (21.6%), followed by hypothyroidism (13.5%), hyperthyroidism (2.7%) and growth hormone deficiency (2.7%). There was wide heterogeneity in the clinical presentation, with late onset of severe hypocalcemia associated with seizure or precipitated in postoperative cardiac surgery, which highlights the importance of continuous follow-up as indicated by the guidelines. Short stature was mainly related to nutritional factors. Growth monitoring is required with the use of syndrome-specific charts and careful monitoring of the growth rate.

CONCLUSION

As previously reported, a significant proportion of patients with endocrine abnormalities were found in this cohort. This highlights that it is essential to carry out an adequate multidisciplinary follow-up, based on the specific clinical guidelines, in order to avoid serious complications such as convulsions due to hypocalcemia. It is important to track size with curves specific to the syndrome and analyze the growth rate.

Prenatal genetic analysis of fetal aberrant right subclavian artery with or without additional ultrasound anomalies in a third level referral center

To evaluate the correlation between chromosomal abnormalities and fetal aberrant right subclavian artery (ARSA) with or without additional ultrasound anomalies (UAs). A total of 340 fetuses diagnosed with ARSA by ultrasound between December, 2015, and July, 2021, were included. All cases were subdivided into three groups: (A) 121 (35.6%) cases with isolated ARSA, (B) 91 (26.8%) cases with soft markers, and (C) 128 (37.6%) cases complicated with other UAs. Invasive testing was performed via amniotic fluid or cord blood karyotyping and chromosomal microarray analysis (CMA) in parallel, and pregnancy outcomes were followed. Karyotype abnormalities were identified in 18/340 (5.3%) patients. Karyotype abnormalities in Groups A, B, and C were 0/121 (0.0%), 7/91 (7.7%), and 11/128 (8.6%), respectively. CMA abnormalities with clinically significant variants were detected in 37/340 (10.9%) cases, of which 22q11.2 deletion syndrome and trisomy 21 accounted for 48.6% (18/37). The overall abnormal CMA with clinically significant variant detection rates in Groups A, B, and C were 3/121(2.5%), 13/91 (14.3%), and 21/128 (16.4%), respectively. There were significant difference in clinically significant CMA anomalies detection rate between Groups A and C (p < 0.05), as well as Groups A and B (p < 0.05). Comparing CMA to karyotyping showed a clinically significant incremental yield in Group C (7.8%, 10/128) compared to Groups A (2.5%, 3/121) and B (6.6%, 6/91) (p > 0.05). Fetal ARSA with additional UAs, concurred with cardiac and extra-cardiac anomalies, constitutes a high-risk factor for chromosomal aberrations, especially for pathogenic or likely pathogenic copy number variants.

22q11 Copy Number Variations in a Brazilian Cohort of Children with Congenital Heart Disorders

Introduction

Congenital heart disease (CHD) is the most common type of congenital defect reported to be one of the leading causes of mortality in the first year of life. Microdeletion and microduplication syndromes (MMS) are associated with cardiac malformations. Understanding which genetic factors are involved in these conditions directly impacts treatment decisions. We aimed to identify the occurrence of genetic alterations and their association with MMS in CHD pediatric patients evaluated in a reference service of Southern Brazil.

Methods

Participants were recruited during 2010 in the intensive care unit of a pediatric hospital. MMs and regions of chromosome 22 were screened by SALSA MLPA Probemix P245 Microdeletion Syndromes-1A kit for detection of copy number variations (CNVs).

Results

MMS were detected in 11 from 207 patients (5.3%). Heterozygous deletion in the 22q11.2 chromosome region was the most prevalent CNV (5 from 11 patients). Also, atypical RTDR1 deletion and 22q11.2 duplication were detected. MLPA was able to reveal microdeletions in SNRPN and NF1 genes in patients with a normal karyotype and FISH.

Conclusion

Our study reports the prevalence and variability of genomic alterations associated with MMS in CHD pediatric patients. The results by MLPA are of great help in planning and specialized care.

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

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Aortic Arch Laterality in Chromosome 22q11.2 Deletion Syndrome: Male-Female Difference

We reviewed patients with chromosome 22q11.2 deletion syndrome. We analyzed cardiovascular findings in patients with confirmed chromosome 22q11.2 deletion syndrome live-born in Nevada between March 2007 and September 2020. We identified 60 patients. Of the 60 patients, 32 (53%) were female. Of the 60, 48 (80%) had a conotruncal abnormality (including isolated vascular rings): 23 of 32 (72%) for females versus 25 of 28 (89%) for males, P = .41. However, 11 (34%) of 32 females had a right aortic arch; whereas, 21 (75%) of 28 males had a right aortic arch, P = .007. In conclusion, in our patient cohort, we found conotruncal malformations were common. However, we noted males were statistically more likely to have a right aortic arch than females. To the best of our knowledge, this male-female aortic arch laterality difference in patients with chromosome 22q11.2 deletion syndrome has not been previously noted.

Deletion Syndrome 22q11.2: A Systematic Review

22q11.2 deletion syndrome (DS 22q11.2) is a rare disease of genetic origin, caused by the loss of the q11.2 region of chromosome 22. It affects one in 4000 live newborns, and among the clinical manifestations that can occur in this syndrome are abnormalities in the parathyroid glands (producing calcium deficits), the palate, the heart and the thymus. It is also known as DiGeorge syndrome or velocardiofacial syndrome, among other names, depending on the clinical presentation of each individual. The main objective of the review was to update information on DS 22q11.2 from publications in the scientific literature. The daily activities of these patients are seriously impaired, due to the impact of the clinical manifestations. Interventions can be performed to improve their social, cognitive and emotional skills, thus increasing their ability to perform different daily activities.

Fetal Aberrant Right Subclavian Artery: Associated Anomalies, Genetic Etiology, and Postnatal Outcomes in a Retrospective Cohort Study

BACKGROUND

Aberrant right subclavian artery (ARSA) is becoming increasingly common in fetuses. However, there are relatively fewer studies regarding the genetic etiology of ARSA. We performed a genetic analysis of fetuses with ARSA and followed up on the pregnancy outcomes to evaluate the prognosis of the fetuses, providing information for prenatal and eugenic consultations.

METHODS

This retrospective study included 112 pregnant females whose fetuses were diagnosed with ARSA from December 2016 to February 2021. Fetal karyotype analysis and single-nucleotide polymorphism (SNP) array were performed.

RESULTS

The 112 fetuses were divided into two groups: the isolated ARSA group (n = 48, 42.9%) and the non-isolated ARSA group (ARSA with other ultrasound abnormalities, n = 64, 57.1%). The total rate of pathogenic copy number variation (CNV) observed using karyotype analysis (3/8) and SNP array (5/8) was 7.1% (8/112). The rates of pathogenic CNV in the isolated and non-isolated ARSA groups were 4.2% (2/48) and 9.4% (6/64), respectively. No significant difference was observed between the two groups (P = 0.463). The results of genetic analysis influenced the parents' decision to terminate the pregnancy. During the follow-up examination, fetuses with ARSA without pathogenic CNV were found to have normal growth and development after birth.

CONCLUSION

Fetuses with isolated ARSA have a low probability of being diagnosed with pathogenic CNV. However, when ARSA is complicated with other ultrasound abnormalities, the risk of pathogenic CNV remarkably increases. Prenatal genetic counseling and SNP-array should be recommended for better assessment of fetal prognosis.

The Oral Health of Patients with DiGeorge Syndrome (22q11) Microdeletion: A Case Report

Background

DiGeorge syndrome (DG) is a genetic disorder associated with 22q11 deletion. It involves various phenotypes, including craniofacial abnormalities, congenital heart disorders, endocrine dysfunction, cognitive deficits, and psychiatric disorders. Cases commonly involve multiple anomalies. However, little is known about the condition of the oral cavity in this disorder, although palate fissure, abnormal mandible, malocclusion, and tooth hypoplasia have been identified. We aimed to determine the odontological features of patients with 22q11.2 microdeletion, in relation to gingival health and oral hygiene. We report the systemic manifestations of nine patients and results of oral evaluation of two patients. In the oral examination, oral hygiene and gingivitis were evaluated.

Case Presentation

In terms of the systemic manifestations, we found high frequencies of low weight and height at birth. In terms of the oral manifestations, both examined patients presented malocclusion, enamel hypoplasia, dental crowding, anodontia, and healthy periodontium.

Conclusion

Although DG has been documented to involve periodontium disease, the patients in this study exhibited more dental manifestations such as enamel defects, misalignment between the teeth and the two dental arches, anodontia, and dental crowding. As such, a multidisciplinary approach combining dentistry and healthcare is recommended in this case.

CNVs in the 22q11.2 Chromosomal Region Should Be an Early Suspect in Infants with Congenital Cardiac Disease

BACKGROUND

Congenital heart disease (CHD) is the most common congenital malformation, it is frequently found as an isolated defect, and the etiology is not completely understood. Although most of the cases have multifactorial causes, they can also be secondary to chromosomal abnormalities, monogenic diseases, microduplications or microdeletions, among others. Copy number variations (CNVs) at 22q11.2 are associated with a variety of symptoms including CHD, thymic aplasia, and developmental and behavioral manifestations. We tested CNVs in the 22q11.2 chromosomal region by MLPA in a cohort of Colombian patients with isolated CHD to establish the frequency of these CNVs in the cohort.

METHODS

CNVs analysis of 22q11.2 by MLPA were performed in 32 patients with apparently isolate CHD during the neonatal period. Participants were enrolled from different hospitals in Bogotá, and they underwent a clinical assessment by a cardiologist and a clinical geneticist.

RESULTS

CNVs in the 22q11.2 chromosomal region were found in 7 patients (21.9%). The typical deletion was found in 6 patients (18.75%) and atypical 1.5 Mb duplication was found in 1 patient (3.1%).

CONCLUSIONS

CNVs in 22q11.2 is a common finding in patients presenting with isolated congenital cardiac disease, therefore these patients should be tested early despite the absence of other clinical manifestations. MLPA is a very useful molecular method and provides an accurate diagnosis.

The Role of Epigenetics in Congenital Heart Disease

Congenital heart disease (CHD) is the most common birth defect among newborns worldwide and contributes to significant infant morbidity and mortality. Owing to major advances in medical and surgical management, as well as improved prenatal diagnosis, the outcomes for these children with CHD have improved tremendously so much so that there are now more adults living with CHD than children. Advances in genomic technologies have discovered the genetic causes of a significant fraction of CHD, while at the same time pointing to remarkable complexity in CHD genetics. For this reason, the complex process of cardiogenesis, which is governed by multiple interlinked and dose-dependent pathways, is a well investigated process. In addition to the sequence of the genome, the contribution of epigenetics to cardiogenesis is increasingly recognized. Significant progress has been made dissecting the epigenome of the heart and identified associations with cardiovascular diseases. The role of epigenetic regulation in cardiac development/cardiogenesis, using tissue and animal models, has been well reviewed. Here, we curate the current literature based on studies in humans, which have revealed associated and/or causative epigenetic factors implicated in CHD. We sought to summarize the current knowledge on the functional role of epigenetics in cardiogenesis as well as in distinct CHDs, with an aim to provide scientists and clinicians an overview of the abnormal cardiogenic pathways affected by epigenetic mechanisms, for a better understanding of their impact on the developing fetal heart, particularly for readers interested in CHD research.

Defining Risk of Postoperative Obstructive Sleep Apnea in Patients With 22q11.2DS Undergoing Pharyngeal Flap Surgery for Velopharyngeal Dysfunction Using Polysomnographic Evaluation

OBJECTIVE

To determine pre- and postoperative prevalence of obstructive sleep apnea (OSA) in patients with 22q11.2 deletion syndrome (DS) undergoing wide posterior pharyngeal flap (PPF) surgery for velopharyngeal dysfunction (VPD).

DESIGN

Retrospective study using pre- and postoperative polysomnography (PSG) to determine prevalence of OSA. Medical records were reviewed for patients' medical comorbidities. Parents were surveyed about snoring.

SETTING

Academic tertiary care pediatric hospital.

PATIENTS

Forty patients with laboratory confirmed 22q11.2DS followed over a 6-year period.

INTERVENTIONS

Pre- and postoperative PSG, speech evaluation, and parent surveys.

MAIN OUTCOME MEASURE

Severity and prevalence of OSA, defined by obstructive apnea hypopnea index (OAHI), before and after PPF surgery to determine whether PPF is associated with increased risk of OSA.

RESULTS

Mean OAHI did not change significantly after PPF surgery (1.1/h vs 2.1/h, P = .330). Prevalence of clinically significant OSA (OAHI ≥ 5) was identical pre- and postoperatively (2 of 40), with both cases having severe-range OSA requiring positive airway pressure therapy. All other patients had mild-range OSA. Nasal resonance was graded as severe preoperatively in 85% of patients. None were graded as severe postoperatively. No single patient factor or parent-reported concern predicted risk of OSA (OAHI ≥ 1.5).

CONCLUSIONS

Patients with 22q11.2DS are medically complex and are at increased risk of OSA at baseline. Wide PPF surgery for severe VPD does not significantly increase risk of OSA. Careful perioperative planning is essential to optimize both speech and sleep outcomes.

The 22q11.2 Microdeletion in Pediatric Patients with Cleft Lip, Palate, or Both and Congenital Heart Disease: A Systematic Review

The 22q11.2 deletion syndrome (22q11.2DS) is present in approximately 5 to 8% of patients with cleft lip, palate, or both (CL/P) and 75 to 80% of patients with congenital heart disease (CHD). In a literature review, we consider this association of 22q11.2DS in pediatric patients with CL/P and CHD. Early diagnosis of 22q11.2DS in pediatric patients with CL/P and CHD helps to optimize a multidisciplinary treatment approach for 22q11DS. Early diagnosis, thereby, can improve quality of life for these patients and awareness of other potential clinical implications that may require attention throughout the patient's life.

Gene-by-gene interactions associated with the risk of conotruncal heart defects

BACKGROUND

The development of conotruncal heart defects (CTDs) involves a complex relationship among genetic variants and maternal lifestyle factors. In this article, we focused on the interactions between 13 candidate genes within folate, homocysteine, and transsulfuration pathways for potential association with CTD risk.

METHODS

Targeted sequencing was used for 328 case-parental triads enrolled in the National Birth Defects Prevention Study (NBDPS). To evaluate the interaction of two genes, we applied a conditional logistic regression model for all possible SNP pairs within two respective genes by contrasting the affected infants with their pseudo-controls. The findings were replicated in an independent sample of 86 NBDPS case-parental triads genotyped by DNA microarrays. The results of two studies were further integrated by a fixed-effect meta-analysis.

RESULTS

One SNP pair (i.e., rs4764267 and rs6556883) located in gene MGST1 and GLRX, respectively, was found to be associated with CTD risk after multiple testing adjustment using simpleM, a modified Bonferroni correction approach (nominal p-value of 4.62e-06; adjusted p-value of .04). Another SNP pair (i.e., rs11892646 and rs56219526) located in gene DNMT3A and MTRR, respectively, achieved marginal significance after multiple testing adjustment (adjusted p-value of .06).

CONCLUSION

Further studies with larger sample sizes are needed to confirm and elucidate these potential interactions.

Risk factors of clinical dysimmune manifestations in a cohort of 86 children with 22q11.2 deletion syndrome: A retrospective study in France

In this study, we describe the biological immune profiles and clinical dysimmune manifestations (infections, autoimmune diseases, and allergies) of patients with 22q11.2 deletion syndrome with the aim of determining risk factors for clinical events. This retrospective study concerned all the patients with 22q11 deletion syndrome attending the Montpellier University Hospital from January 1, 1992, to December 31, 2014 who had at least one immune investigation before the age of 18. We analyzed the clinical features, biological tests and the course of infections, autoimmunity, and allergy of 86 children. Among these 86 children, 48 (59%) had a low T lymphocyte level. Twenty-nine patients (34%) had a severe infection. The only risk factor for severe infection was the low level of CD4+ T-cells (OR: 3.3; 95% confidence interval (CI) [1.020-11.108]). Eleven patients (13%) developed an autoimmune disease; the only risk factor was an antecedent of severe infection (OR: 4.1; 95% CI [1.099-15.573]). Twenty-three patients (27%) had allergic episodes. A low level of CD8+ T-cells (OR: 3.2; 95% CI [1.07-9.409]) was significantly associated with allergy manifestations. Patients with 22q11 deletion syndrome have a high rate of dysimmune manifestations. We found statistic correlations among CD4+ T-cell count, infectious manifestations, and autoimmunity.

A case report of T-box 1 mutation causing phenotypic features of chromosome 22q11.2 deletion syndrome

Background

The heterozygous microdeletion of chromosome 22q11.2 results in a spectrum of disorders, including DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS), with phenotypic features that can include the classic triad of congenital heart disease (CHD), thymic aplasia and hypoparathyroidism. Such microdeletions are usually detectable by fluorescence in situ hybridization (FISH).

Case presentation

We report a case of a twenty-three year-old female who presented with clinical features of chromosome 22q11.2 deletion syndrome including cardiac anomalies, hypoparathyroidism and dysmorphic facial features. FISH did not reveal a 22q11.2 microdeletion. Further genetic analysis showed T box-1 (TBX1) heterozygous mutation.

Conclusions

The TBX1 gene plays a significant role in the development of fourth pharyngeal arch structures. Mutations of TBX1, which is found at chromosome 22q11.21 can be responsible for the development of syndromes classically associated with chromosome 22q11.2 deletions. This case emphasizes that the TBX1 gene, among other genes, can be responsible for the developmental anomalies seen in these syndromes.

Pharyngeal flap using carotid artery mobilization in 22q11.2 deletion syndrome with velopharyngeal insufficiency

INTRODUCTION

22q11.2 deletion syndrome is the most common microdeletion syndrome in children. Many patients with this disease develop craniofacial defects including cleft palate, bifid uvula, and velopharyngeal insufficiency. Our study adds to the current body of literature by describing a novel technique of carotid mobilization performed in conjunction with pharyngeal flap surgery in patients with extensive medialization of the carotid artery.

METHODS

Carotid artery mobilization followed by insertion of a superiorly based pharyngeal flap was performed on two patients, a 10-year-old girl and a 5-year-old boy, with 22q11.2 deletion syndrome concurrent with velopharyngeal insufficiency.

RESULTS

Neither patient experienced significant post-operative issues. Following the procedure, parents of both patients noted significant speech and voice improvement. Both patients had improvements in VPI Effects On Life Outcome (VELO) scores, nasometry, and production of paragraph passages following surgery.

CONCLUSIONS

Our study describes a novel surgical treatment for children with 22q11.2 deletion syndrome with significant velopharyngeal insufficiency (VPI). The procedure wherein is characterized by an extensive mobilization of the carotid artery followed by implantation of a pharyngeal flap. This technique resulted in no significant intra-operative bleeding, and was measured to be successful as noted by nasometry scores and changes in pre- and post-op VELO scores.

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.

Genetic Imbalances in Argentinean Patients with Congenital Conotruncal Heart Defects

Congenital conotruncal heart defects (CCHD) are a subset of serious congenital heart defects (CHD) of the cardiac outflow tracts or great arteries. Its frequency is estimated in 1/1000 live births, accounting for approximately 10–30% of all CHD cases. Chromosomal abnormalities and copy number variants (CNVs) contribute to the disease risk in patients with syndromic and/or non-syndromic forms. Although largely studied in several populations, their frequencies are barely reported for Latin American countries. The aim of this study was to analyze chromosomal abnormalities, 22q11 deletions, and other genomic imbalances in a group of Argentinean patients with CCHD of unknown etiology. A cohort of 219 patients with isolated CCHD or associated with other major anomalies were referred from different provinces of Argentina. Cytogenetic studies, Multiplex-Ligation-Probe-Amplification (MLPA) and fluorescent in situ hybridization (FISH) analysis were performed. No cytogenetic abnormalities were found. 22q11 deletion was found in 23.5% of the patients from our cohort, 66% only had CHD with no other major anomalies. None of the patients with transposition of the great vessels (TGV) carried the 22q11 deletion. Other 4 clinically relevant CNVs were also observed: a distal low copy repeat (LCR)D-E 22q11 duplication, and 17p13.3, 4q35 and TBX1 deletions. In summary, 25.8% of CCHD patients presented imbalances associated with the disease.

A case of severe TBCE-negative hypoparathyroidism-retardation-dysmorphism syndrome: Case report and literature review

Hypoparathyroidism-retardation-dysmorphism syndrome (HRD) is a rare autosomal recessive disorder attributed to the mutations in the tubulin-specific chaperone E (TBCE) gene, which is vital for microtubule function during mitosis, organelle positioning, and neuronal cytokinesis. HRD is a congenital syndromic hypoparathyroidism associated with growth deficiency, microcephaly, intellectual disability, ocular anomalies, and facial dysmorphism. To our knowledge, there is only one published case of mild HRD-like syndrome with no identifiable genetic etiology. We report a case of severe TBCE-negative phenotypic HRD in a 4-year-old female from India presenting with hypocalcemic seizures due to congenital hypoparathyroidism, extreme microcephaly, growth deficiency, ocular anomalies, and facial dysmorphism. SNP microarray and whole exome sequencing (WES) did not detect any abnormalities in TBCE or other genes of interest. WES revealed two variants of unknown clinical significance in CASC5 gene, which codes for a protein in the kinetochore and, interestingly similar to TBCE, is essential for proper microtubule function during mitosis and cell proliferation and has been implicated in primary microcephaly disorders. However, further targeted sequencing in the parents revealed both variants inherited from the unaffected mother. Significant copy number variant noise in the proband and her parents limited further analysis. At this time the role of variants in the CASC5 gene is unclear and cannot explain our patient's phenotype. In conclusion, we report a severe case of phenotypic HRD syndrome, in which extensive genetic evaluation failed to reveal an etiology. Our case demonstrates that the pathogenesis of HRD may be genetically heterogenous, meriting further genetic investigations.

Gene expression profiling in the developing secondary palate in the absence of Tbx1 function

BACKGROUND

Microdeletion of chromosome 22q11 is associated with significant developmental anomalies, including disruption of the cardiac outflow tract, thymic/parathyroid aplasia and cleft palate. Amongst the genes within this region, TBX1 is a major candidate for many of these developmental defects. Targeted deletion of Tbx1 in the mouse has provided significant insight into the function of this transcription factor during early development of the cardiac and pharyngeal systems. However, less is known about its role during palatogenesis. To assess the influence of Tbx1 function on gene expression profile within the developing palate we performed a microarray screen using total RNA isolated from the secondary palate of E13.5 mouse embryos wild type, heterozygous and mutant for Tbx1.

RESULTS

Expression-level filtering and statistical analysis revealed a total of 577 genes differentially expressed across genotypes. Data were clustered into 3 groups based on comparison between genotypes. Group A was composed of differentially expressed genes in mutant compared to wild type (n = 89); Group B included differentially expressed genes in heterozygous compared to wild type (n = 400) and Group C included differentially expressed genes in mutant compared to heterozygous (n = 88). High-throughput quantitative real-time PCR (RT-PCR) confirmed a total of 27 genes significantly changed between wild type and mutant; and 27 genes between heterozygote and mutant. Amongst these, the majority were present in both groups A and C (26 genes). Associations existed with hypertrophic cardiomyopathy, cardiac muscle contraction, dilated cardiomyopathy, focal adhesion, tight junction and calcium signalling pathways. No significant differences in gene expression were found between wild type and heterozygous palatal shelves.

CONCLUSIONS

Significant differences in gene expression profile within the secondary palate of wild type and mutant embryos is consistent with a primary role for Tbx1 during palatogenesis.

Minor pulmonary malformations in a child

This case report describes an Italian female who was born at full term via Caesarean delivery, performed for breech presentation. She was the first child of healthy, unrelated parents. At birth, she weighed 2600 g (<3rd centile; −2 sd) and measured 45 cm in length (<3rd centile; −2 sd). Psychomotor development was normal for her age. The recommended immunisation schedule was administered. Newborn screening tests (hip ultrasound and acoustic reflexes) as well as echocardiography were normal. There was no known maternal exposure to teratogens or infections. The family history was unremarkable, except for retinitis pigmentosa and hypothyroidism (in the mother).

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Hypoparathyroidism concomitant with macrothrombocytopenia in an elderly woman with 22q11.2 deletion syndrome

We describe the case of a 62-year-old woman with schizophrenia and intellectual disability, who presented with intermittent muscle cramping for 2 weeks. A dysmorphic face and a positive Trousseau's sign, but without ecchymosis or petechial lesion were noted. Laboratory data revealed impaired renal function (creatinine level = 1.6 mg/dL), severe hypocalcaemia (total calcium level = 5.7 mg/dL) with low urinary calcium excretion (13.2 mg/day), hyperphosphatemia (phosphate level = 7.3 mg/dL), and low intact parathyroid hormone level (52.5 pg/mL)-indicating primary hypoparathyroidism. A blood smear revealed thrombocytopenia (30,000 thrombocytes/µL) and giant platelets-indicating macrothrombocytopenia. Chromosome 22q11.2 deletion syndrome (22q11.2DS) in the deficient chromosome 22 was confirmed using multiplex ligation-dependent probe amplification showing haploinsufficiency in GP1BB and TBX-1. Cooccurrence of hypoparathyroidism and macrothrombocytopenia in 22q11.2DS is rare and can easily be misdiagnosed as idiopathic thrombocytopenia purpura and inappropriate splenectomy or chemotherapy can aggravate hypoparathyroidism. Early diagnosis of 22q11.2DS, characterized by hypoparathyroidism and macrothrombocytopenia, in elderly patients with schizophrenia can facilitate in avoiding circuitous diagnosis and inappropriate management.

Hypocalcaemia in an adult: the importance of not overlooking the cause

A 58-year-old male patient was admitted at the São Bernardos's Hospital (Setúbal, Portugal) with generalised muscle spasms, dyspnoea, laryngospasm and bronchospasm in the context of severe hypocalcaemia. Despite efforts to correct serum calcium, it remained below average, leading to question the true cause of hypocalcaemia. Low parathyroid hormone and 25-hydroxyvitamin D, along with facial anomalies, palate defect and cognitive impairment with concomitant psychiatric disorder led to a suspicion of a DiGeorge/velocardiofacial/22q11.2 deletion syndrome (DS), which was confirmed through genetic testing. The 22q11.2 DS has a wide phenotypic expression and there are growing reports of diagnosis being made in adulthood. This case report highlights the importance of understanding the cause of refractory hypocalcaemia and alerts medical community to carefully access these patients, for this metabolic disorder may only present in later stages of life.

Screening for fetal chromosomal and subchromosomal disorders

Screening for fetal chromosomal disorders has evolved greatly over the last four decades. Initially, only maternal age-related risks of aneuploidy were provided to patients. This was followed by screening with maternal serum analytes and ultrasound markers, followed by the introduction and rapid uptake of maternal plasma cell-free DNA-based screening. Studies continue to demonstrate that cfDNA screening for common aneuploidies has impressive detection rates with low false-positive rates. The technology continues to push the boundaries of prenatal screening as it is now possible to screen for less common aneuploidies and subchromosomal disorders. The optimal method for incorporating cfDNA screening into existing programs continues to be debated. It is important that obstetricians understand the biological foundations and limitations of this technology and provide patients with up-to-date information regarding cfDNA screening.

22q11.2 rearrangements found in women with low ovarian reserve and premature ovarian insufficiency

Ovarian reserve represents the number of available follicles/oocytes within ovaries and it can be assessed by follicle stimulating hormone levels, anti-Müllerian hormone levels, and/or antral follicle count determined by ultrasounds. A low ovarian reserve is defined by an abnormal ovarian reserve test. This condition can be considered premature if it occurs before the age of 40, leading to premature ovarian insufficiency. Despite the growing knowledge concerning the genetic basis of ovarian deficiency, the majority of cases remain without a genetic diagnosis. Although 22q11.2 deletions and duplications have been associated with genitourinary malformations, ovarian deficiency is not a commonly reported feature. We report here four patients bearing a 22q11.2 rearrangement, identified during the clinical assessment of their low ovarian reserve or premature ovarian insufficiency, and discuss the molecular basis of the ovarian defects.

Hypocalcemia due to 22q11.2 deletion syndrome diagnosed in adulthood

Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a genetic syndrome that may present with hypocalcemia due to primary hypoparathyroidism (PH) at any age. We report a new diagnosis of 22q11.2DS in a 57-year-old man who presented with symptomatic hypocalcemia. It is important to consider genetic causes of hypocalcemia due to PH regardless of age.

Learning points

It is important to discard genetic cause of primary hypoparathyroidism in a patient without autoimmune disease or prior neck surgery.A new diagnosis of a hereditary disease has familial implications and needs genetic counselling.It is also important to discard other syndrome's comorbidities.

Visual processing deficits in 22q11.2 Deletion Syndrome

Carriers of the rare 22q11.2 microdeletion present with a high percentage of positive and negative symptoms and a high genetic risk for schizophrenia. Visual processing impairments have been characterized in schizophrenia, but less so in 22q11.2 Deletion Syndrome (DS). Here, we focus on visual processing using high-density EEG and source imaging in 22q11.2DS participants (N = 25) and healthy controls (N = 26) with an illusory contour discrimination task.

Significant differences between groups emerged at early and late stages of visual processing. In 22q11.2DS, we first observed reduced amplitudes over occipital channels and reduced source activations within dorsal and ventral visual stream areas during the P1 (100–125 ms) and within ventral visual cortex during the N1 (150–170 ms) visual evoked components. During a later window implicated in visual completion (240–285 ms), we observed an increase in global amplitudes in 22q11.2DS. The increased surface amplitudes for illusory contours at this window were inversely correlated with positive subscales of prodromal symptoms in 22q11.2DS.

The reduced activity of ventral and dorsal visual areas during early stages points to an impairment in visual processing seen both in schizophrenia and 22q11.2DS. During intervals related to perceptual closure, the inverse correlation of high amplitudes with positive symptoms suggests that participants with 22q11.2DS who show an increased brain response to illusory contours during the relevant window for contour processing have less psychotic symptoms and might thus be at a reduced prodromal risk for schizophrenia.

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In schizophrenia, early visual processing is altered.

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22q11.2DS carriers have an increased risk for schizophrenia.

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Hd-EEG to investigate visual processing in an illusory contour task in 22q11.2DS.

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Occipital cortex activity is reduced in 22q11.2DS early in time.

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Both in 22q11.2DS and schizophrenia, early visual processing is impaired at P1.

TBX1 loss-of-function mutation contributes to congenital conotruncal defects

Conotruncal defects (CTDs) account for ~30% of all types of congenital heart disease and contribute to increased morbidity and mortality rates. Increasing evidence suggests that genetic risk factors are involved in the pathogenesis of CTDs. Mutations in a number of genes, including the TBX1 gene that codes for a T-box transcription factor essential for normal cardiovascular development, may contribute to the development of CTD. CTDs are genetically heterogeneous and the genetic defects responsible for CTDs in the majority of patients remain unknown. The present study sequenced the coding regions and splicing junction boundaries of TBX1 in 136 patients with CTDs and 300 matched healthy individuals. The disease-causing potential of the identified TBX1 sequence variation was evaluated using MutationTaster, PolyPhen-2, SIFT and PROVEN software. The functional characteristics of the mutant TBX1 gene were defined using a dual-luciferase reporter assay system. A novel heterozygous TBX1 mutation, p.S233Y, was identified in a patient with transposition of the great arteries (TGA) and a ventricular septal defect. This mutation was absent in the 300 controls and altered the amino acid produced, serine, which is evolutionarily conserved across several species, and was predicted to be pathogenic in silico. Luciferase assays conducted in COS-7 cells demonstrated that the newly identified TBX1 mutation was associated with significantly diminished transcriptional activation of the ANF promoter compared with the wild-type TBX1. To the best of our knowledge, the present study is the first to associate a TBX1 loss-of-function mutation with enhanced susceptibility to TGA, which adds significant insight to the molecular mechanism of TGA.

[22q11.2 microdeletion syndrome: Analysis of the care pathway before the genetic diagnosis]

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a very broad phenotypic spectrum disorder. It can affect many organs or systems. 22q11.2DS is the most common microdeletion syndrome in humans, with a prevalence ranging from one in every 2000 to one in 4000 newborns. It seems to be more prevalent than reported and under-recognized or undiagnosed because of its inherent clinical variability and heterogeneity. In France, 15,000 patients may be affected by this disease, more than half without knowing it. The aim of this study was to analyze the care pathway before the genetic diagnosis of 22q11.2DS.

METHODS

We conducted a single-center, retrospective analysis of postnatally diagnosed patients recruited by the cytogenetic laboratory of Nancy (France) from January 2000 to December 2015. Clinical data were first collected by consulting the medical files of patients and then by calling them directly. Written informed consent was obtained and the study was approved by local research ethics boards. Data concerned only clinical features before the diagnosis.

RESULTS

The cohort consisted of 32 individuals with 22q11.2DS. The average age at diagnosis was 9 years and 2 months and the median age was 2 years and 11 months. Fetal echography was abnormal in 15 pregnancies. During the neonatal period, the most important features were eating difficulties and congenital malformations (n=20), with a majority of complex heart diseases (n=16), dominated by conotruncal malformations (n=6). In case of malformation, the average age at diagnosis decreased to 2 years and 6 months. A congenital heart disease brought the average age of diagnosis down to 2 years and 6 months. Hypocalcemia and dysmorphism were also classical features (n=14). Before the age of 3 years, speech delay occurred in nine patients. After 3 years of age, rhinolalia was predominant (n=11). Academic disabilities were present in all subjects. At least 14 patients had a de novo deletion. Five patients were diagnosed within genetic counseling, with the deletion was inherited from the mother in three out of four cases. One was the monozygotic twin of a patient. Seven patients were diagnosed as adults. Four of them were diagnosed only because of the clinical presentation of their children or fetuses. Retrospectively, all adult patients had clinical signs suggesting the 22q11.2DS diagnosis. Relational disorders affected eight patients. None of them had been referred to the geneticist for this reason. In most cases, the pediatric cardiologist referred patients to the geneticist (n=9). Physiotherapists (n=15) and speech-language pathologists (n=12) were frequently requested but did not participate in the diagnosis.

CONCLUSION

The present study highlights the difficulty of establishing the diagnosis when the major features of the 22q11.2DS are absent during the 1st months of life. This is particularly true when there is no congenital defect. Special attention must be given to speech disorders in childhood and neuropsychological disorders later in life. The association between 22q11.2DS and early-onset parkinson disease implies that adult neurologists should be aware of this diagnosis. For adult patients, familial occurrence is the most frequent cause of diagnosis in spite of clinical signs suggestive of 22q11.2DS. The management of these patients involves better information of medical and paramedical staff in order to refer them to the geneticist earlier in life.

A Comprehensive Craniofacial Study of 22q11.2 Deletion Syndrome

The 22q11.2 deletion syndrome (22q11.2DS) is one of the most frequent microdeletion syndromes and presents with a highly variable phenotype. In most affected individuals, specific but subtle facial features can be seen. In this observational study, we aim to investigate the craniofacial and dental features of 20 children with a confirmed diagnosis of 22q11.2DS by analyzing 3-dimensional (3D) facial surface scans, 2-dimensional (2D) clinical photographs, panoramic and cephalometric radiographs, and dental casts. The 3D facial scans were compared to scans of a healthy control group and analyzed using a spatially dense geometric morphometric approach. Cephalometric radiographs were digitally traced, and measurements were compared to existing standards. Occlusal and dental features were studied on dental casts and panoramic radiographs. Interestingly, a general trend of facial hypoplasia in the lower part of the face could be evidenced with the 3D facial analysis in children with 22q11.2DS compared to controls. Cephalometric analysis confirmed a dorsal position of the mandible to the maxilla in 2D and showed an enlarged cranial base angle. Measurements for occlusion did not differ significantly from standards. Despite individual variability, we observed a retruded lower part of the face as a common feature, and we also found a significantly higher prevalence of tooth agenesis in our cohort of 20 children with 22q11.2DS (20%). Furthermore, 3D facial surface scanning proved to be an important noninvasive, diagnostic tool to investigate external features and the underlying skeletal pattern.

Partial microduplication in the histone acetyltransferase complex member KANSL1 is associated with congenital heart defects in 22q11.2 microdeletion syndrome patients

22q11.2 microdeletion syndrome (22q11.2DS) is the most common microdeletion disorder in humans, with an incidence of 1/4000 live births. It is caused by a heterozygous deletion of 1.5–3 Mb on chromosome region 22q11.2. Patients with the deletion present features that include neuropsychiatric problems, craniofacial abnormalities and cardiovascular malformations. However, the phenotype is highly variable and the factors related to the clinical heterogeneity are not fully understood. About 65% of patients with 22q11.2DS have congenital heart defects (CHD). The main goal of this study was to identify common CNVs in 22q11.2DS patients that could be associated with the incomplete penetrance of CHD. Analysis of genomic DNA from 253 patients with 22q11.2DS using array technology showed an association between a microduplication located in region 17q21.31 and CHD (p-value = 0.023, OR = 2.75, 95% CI = 1.17–7.03). This region includes the first three exons of KANSL1 gene. Bioinformatic analysis showed that KANSL1 and CRKL, a gene in the commonly deleted region of 22q11.2DS, are part of the same regulatory module in a miRNA-mRNA network. These results show that a KANSL1 microduplication, in combination with the 22q11.2 deletion, is associated with increased risk of CHD in these patients, suggesting that KANSL1 plays a role as a modifier gene in 22q11.2DS patients.

Genetic Evaluation for Craniofacial Conditions

There are thousands of craniofacial disorders, each with a different etiology. All cases of orofacial clefts have an underlying genetic cause, ranging from multifactorial with an underlying genetic predisposition to chromosomal and single-gene etiologies. More than 50% of cases of Pierre Robin sequence are syndromic and 25% of craniosynostoses are syndromic. Clinical genetics evaluation is important for each patient with a craniofacial condition to make a proper diagnosis, counsel the family, and assist in management. This is an overview of the major components of the clinical genetics evaluation with a review of many syndromes associated with craniofacial disorders.

A Case of 22q11 Deletion Syndrome (22q11DS) with a Panayiotopoulos Epileptic Pattern: Are Additional Copy-Number Variations a Possible Second Hit in Modulating the 22q11DS Phenotype?

"22q11 deletion syndrome" (22q11DS) is a rare genetic syndrome, in which most patients share the same deletion, but their clinical features may vary a great deal. The genetic mechanisms underlying the variable expressivity and reduced penetrance of 22q11DS still have to be fully elucidated. Epilepsy has been reported in about 15.2% of the patients; however, few studies have focused on this topic, and in most cases, a detailed epileptic profile is missing. Since only a minority of patients experience epileptic seizures, 22q11deletion can be considered a predisposing factor, which is not sufficient "per se" to cause epilepsy; to date, no candidate gene for epilepsy has been identified in the deleted region. We report on a 6-year-old girl with 22q11DS presenting a form of epilepsy that can be classified as "Panayiotopoulos syndrome." Array CGH revealed an additional microduplication of 172 kb in 2q37, harboring three genes. One of these, DGKD (diacylglycerol kinase delta), is interrupted by the distal breakpoint of the duplication. DGKD encodes a cytoplasmic enzyme that phosphorylates diacylglycerol to produce phosphatidic acid. This is an important second messenger in a pathway of lipid signaling that has been implicated in epilepsy and other neurological diseases. Disruption of DGKD by a t(X;2) has been previously reported in a patient with epilepsy. The 2q37 microduplication was inherited from her mother, who never experienced epileptic seizures, thus this imbalance is not "per se" sufficient to cause epilepsy. It can be hypothesized that the epileptic phenotype is provoked by the simultaneous presence of 22q11.2 deletion and 2q37 duplication. It has been shown that rare additional copy-number variations (CNVs) outside the 22q11.2 region may modulate the risk of congenital heart defects. It is possible that also for the epileptic phenotype, the additional CNVs may represent an important modifying factor underlying the variable expressivity and incomplete penetrance in the 22q11DS.

Camptodactyly and the 22q11.2 deletion syndrome

We describe a 5-day-old male with minor facial anomalies, a congenital laryngeal web, severe laryngomalacia, and prominent fixed flexion of the proximal interphalangeal joints of digits 2 through 5 bilaterally. A whole genome SNP microarray analysis identified a 2.55 Mb interstitial deletion of 22q11.21, typical of that seen in the DiGeorge and Velocardiofacial syndromes. A review of the literature identifies 10 other cases with camptodactyly. Camptodactyly appears to be an associated but rarely reported anomaly in patients with the 22q11.2 microdeletion syndrome. © 2016 Wiley Periodicals, Inc.

HIRA Gene is Lower Expressed in the Myocardium of Patients with Tetralogy of Fallot

Background:

The most typical cardiac abnormality is conotruncal defects (CTDs) in patients with 22q11 deletion syndrome (22q11DS). HIRA (histone cell cycle regulator) gene, as one of the candidate genes located at the critical region of 22q11DS, was reported as possibly relevant to CTD in animal models. This study aimed to analyze the level of expression of the HIRA gene in tetralogy of Fallot (TOF) patients and the potential DNA sequence variations in the promoter region.

Methods:

The messenger RNA (mRNA) expression was examined with quantitative real-time polymerase chain reaction in 39 myocardial tissues of the right ventricular outflow tract (RVOT) from TOF patients and 4 myocardial tissues of RVOT from noncardiac death children. The protein expression was detected using immunohistochemistry in 12 TOF patients and 4 controls. A total of 100 TOF cases and 200 healthy controls were recruited for DNA sequencing.

Results:

The mRNA and protein expressions of the HIRA gene in the myocardium of the TOF patients were both significantly lower as compared to the controls (P < 0.05). Five single nucleotide polymorphisms (SNPs), including g.4111A>G (rs1128399), g.4265C>A (rs4585115), g.4369T>G (rs2277837), g.4371C>A (rs148516780), and g.4543T>C (rs111802956), were found in the promoter region of the HIRA gene. There were no significant differences of frequencies in these SNPs between the TOF patients and the controls (P > 0.05).

Conclusion:

The abnormal lower expression of the HIRA gene in the myocardium may participate in the pathogenesis of TOF.

MECHANISMS IN ENDOCRINOLOGY: Novel genetic causes of short stature

The fast technological development, particularly single nucleotide polymorphism array, array-comparative genomic hybridization, and whole exome sequencing, has led to the discovery of many novel genetic causes of growth failure. In this review we discuss a selection of these, according to a diagnostic classification centred on the epiphyseal growth plate. We successively discuss disorders in hormone signalling, paracrine factors, matrix molecules, intracellular pathways, and fundamental cellular processes, followed by chromosomal aberrations including copy number variants (CNVs) and imprinting disorders associated with short stature. Many novel causes of GH deficiency (GHD) as part of combined pituitary hormone deficiency have been uncovered. The most frequent genetic causes of isolated GHD are GH1 and GHRHR defects, but several novel causes have recently been found, such as GHSR, RNPC3, and IFT172 mutations. Besides well-defined causes of GH insensitivity (GHR, STAT5B, IGFALS, IGF1 defects), disorders of NFκB signalling, STAT3 and IGF2 have recently been discovered. Heterozygous IGF1R defects are a relatively frequent cause of prenatal and postnatal growth retardation. TRHA mutations cause a syndromic form of short stature with elevated T3/T4 ratio. Disorders of signalling of various paracrine factors (FGFs, BMPs, WNTs, PTHrP/IHH, and CNP/NPR2) or genetic defects affecting cartilage extracellular matrix usually cause disproportionate short stature. Heterozygous NPR2 or SHOX defects may be found in ∼3% of short children, and also rasopathies (e.g., Noonan syndrome) can be found in children without clear syndromic appearance. Numerous other syndromes associated with short stature are caused by genetic defects in fundamental cellular processes, chromosomal abnormalities, CNVs, and imprinting disorders.

A ceRNA approach may unveil unexpected contributors to deletion syndromes, the model of 5q- syndrome

In genomic deletions, gene haploinsufficiency might directly configure a specific disease phenotype. Nevertheless, in some cases no functional association can be identified between haploinsufficient genes and the deletion-associated phenotype. Transcripts can act as microRNA sponges. The reduction of transcripts from the hemizygous region may increase the availability of specific microRNAs, which in turn may exert in-trans regulation of target genes outside the deleted region, eventually contributing to the phenotype. Here we prospect a competing endogenous RNA (ceRNA) approach for the identification of candidate genes target of epigenetic regulation in deletion syndromes. As a model, we analyzed the 5q- myelodysplastic syndrome. Genes in haploinsufficiency within the common 5q deleted region in CD34+ blasts were identified in silico. Using the miRWalk 2.0 platform, we predicted microRNAs whose availability, and thus activity, could be enhanced by the deletion, and performed a genomewide analysis of the genes outside the 5q deleted region that could be targeted by the predicted miRNAs. The analysis pointed to two genes with altered expression in 5q- transcriptome, which have never been related with 5q- before. The prospected approach allows investigating the global transcriptional effect of genomic deletions, possibly prompting discovery of unsuspected contributors in the deletion-associated phenotype. Moreover, it may help in functionally characterizing previously reported unexpected interactions.