22q11.2 microduplication syndrome with associated esophageal atresia/tracheo-esophageal fistula and vascular ring

Identification of a novel MAG gene mutation with 22q11.21 microduplication linked to hereditary spastic paraplegia

Diagnosing hereditary spastic paraplegia (HSP) in paediatric patients can be challenging, especially when there is no positive family history. Children are often initially misdiagnosed with cerebral palsy due to the gradual progression of the disease and non-specific neuroimaging findings, despite the absence of perinatal insult. This misdiagnosis can prevent timely prenatal diagnosis, limiting the ability to make informed decisions about the pregnancy and to plan early interventions. Homozygous variants in the MAG gene, encoding myelin-associated glycoprotein (MAG), have been associated with complicated forms of HSP. In this study, we identified a novel mutation suggestive of an apparently homozygous variant of the MAG gene with deletion in exon 5 (c.451del (p.Ala151GlnfsTer22)) that is predicted to result in a frameshift and premature truncation of the protein 22 amino acids downstream to codon 151. This variant was of pathological significance in our patient who presented with cerebellar ataxia, nystagmus and hypotonia, gradually progressing to spastic paraplegia. Therefore, identifying these variants helps in understanding the underlying genetic factors contributing to HSP, aiding in correct diagnosis.

Perioperative and Anesthetic Considerations in Vascular Rings and Slings

Vascular rings represent an increasingly prevalent and diverse set of congenital malformations in which the aortic arch and its primary branches encircle and constrict the esophagus and trachea. Perioperative management varies significantly based on the type of lesion, its associated comorbidities, and the compromise of adjacent structures. Multiple review articles have been published describing the scope of vascular rings and relevant concerns from a surgical perspective. This review seeks to discuss the perioperative implications and recommendations of such pathology from the perspective of an anesthesia provider.

Omenn syndrome in a 10-month-old male with athymia and VACTERL association

We describe the case of a 10-month-old boy with vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb abnormalities (VACTERL) association and athymia who developed Omenn syndrome.

Esophageal Atresia With or Without Tracheoesophageal Fistula: Comorbidities, Genetic Evaluations, and Neonatal Outcomes

Objective Esophageal atresia with or without tracheoesophageal fistula (EA/TEF) has a reported incidence of 1 in 3500 live births and requires intensive care and surgery. To evaluate the prevalence of a molecularly confirmed genetic etiology of EA/TEF in a level IV neonatal intensive care unit (NICU), focusing on genetic evaluation, diagnostic yield, and clinical outcomes of these neonates. Study design A retrospective cohort study over a period of seven years was performed for all patients admitted with a diagnosis of EA/TEF. Automated data was extracted for demographic information and manual extraction was done to evaluate the frequency of associated anomalies, type of genetic evaluations and diagnoses, and outcomes at NICU discharge. Results Sixty-eight infants met the inclusion criteria. The majority were male (n=42; 62%), born at >37 weeks' gestation (n=36; 53%), and had EA with distal TEF (n=54; 79%). Most (n=53; 78%) had additional associated congenital anomalies, but only 47 (69%) patients had a genetics evaluation performed and genetic testing was sent for 44 (65%) of those patients. The most common genetic testing performed was chromosomal microarray analysis (n=40; 59%), followed by chromosome analysis (n=11; 16%), and whole exome/genome sequencing (n=7; 10%). Five unique genetic diagnoses including CHARGE Syndrome, Fanconi Syndrome, EFTUD2-related mandibulofacial dysostosis, and two different chromosomal deletion syndromes were made for a total of nine (13%) patients in our cohort. The cohort suffered a high rate of morbidity and mortality during their NICU stay with important differences noted in isolated vs non-isolated EA/TEF. Twelve infants (18%) died prior to NICU discharge. Of those surviving, 40 (71%) infants had a primary repair, 37 (66%) infants required G or GJ feedings at NICU discharge, and eight (14%) patients were discharged on some type of respiratory support. Conclusion In this high-risk cohort of EA/TEF patients cared for at a quaternary NICU, a majority were non-isolated and had some form of a genetic evaluation, but a minority underwent exome or genome sequencing. Given the high prevalence of associated anomalies, high mortality, and genetic disease prevalence in this cohort, we recommend standardization of phenotyping and genetic evaluation to allow for precision care and appropriate risk stratification.

Phenotypic Characteristics and Copy Number Variants in a Cohort of Colombian Patients with VACTERL Association

VACTERL association (OMIM 192350) is a heterogeneous clinical condition characterized by congenital structural defects that include at least 3 of the following features: vertebral abnormalities, anal atresia, heart defects, tracheoesophageal fistula, renal malformations, and limb defects. The nonrandom occurrence of these malformations and some familial cases suggest a possible association with genetic factors such as chromosomal alterations, gene mutations, and inherited syndromes such as Fanconi anemia (FA). In this study, the clinical phenotype and its relationship with the presence of chromosomal abnormalities and FA were evaluated in 18 patients with VACTERL association. For this, a G-banded karyotype, array-comparative genomic hybridization, and chromosomal fragility test for FA were performed. All patients (10 female and 8 male) showed a broad clinical spectrum: 13 (72.2%) had vertebral abnormalities, 8 (44.4%) had anal atresia, 14 (77.8%) had heart defects, 8 (44.4%) had esophageal atresia, 10 (55.6%) had renal abnormalities, and 10 (55.6%) had limb defects. Chromosomal abnormalities and FA were ruled out. In 2 cases, the finding of microalterations, namely del(15)(q11.2) and dup(17)(q12), explained the phenotype; in 8 cases, copy number variations were classified as variants of unknown significance and as not yet described in VACTERL. These variants comprise genes related to important cellular functions and embryonic development.

Atypical 22q11.2 Microduplication with "Typical" Signs and Overgrowth

The 22q11.2 microduplication syndrome shows variable phenotypes with reduced penetrance compared to the 22q11.2 deletion syndrome. We report a woman with overgrowth and macrocephaly, mild mental retardation, heart defect, kidney anomalies, and dysmorphic features. Array-CGH analysis revealed a 246-kb duplication at the 22q11.2 region. No additional clinically significant CNVs were found. The case resembles a previously published case also showing overgrowth and macrocephaly with an almost identical 22q11.2 duplication of 252 kb.

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.

Genotype-phenotype correlation in 75 patients with small supernumerary marker chromosomes

Background

Small supernumerary marker chromosomes (sSMCs) are rare structural abnormalities in the population; however, they are frequently found in children or fetuses with hypoevolutism and infertile adults. sSMCs are usually observed first by karyotyping, and further analysis of their molecular origin is important in clinical practice. Next-generation sequencing (NGS) combined with Sanger sequencing helps to identify the chromosomal origins of sSMCs and correlate certain sSMCs with a specific clinical picture.

Results

Karyotyping identified 75 sSMCs in 74,266 samples (0.1% incidence). The chromosomal origins of 27 of these sSMCs were detected by sequencing-related techniques (NGS, MLPA and STR). Eight of these sSMCs are being reported for the first time. sSMCs mainly derived from chromosomal X, Y, 15, and 18, and some sSMC chromosomal origins could be correlated with clinical phenotypes. However, the chromosomal origins of the remaining 48 sSMC cases are unknown. Thus, we will develop a set of economical and efficient methods for clinical sSMC diagnosis.

Conclusions

This study details the comprehensive characterization of 27 sSMCs. Eight of these sSMCs are being reported here for the first time, providing additional information to sSMC research. Identifying sSMCs may reveal genotype-phenotype correlations and integrate genomic data into clinical care.

Caudal Regression Syndrome-A Review Focusing on Genetic Associations

Caudal regression syndrome (CRS) represents a spectrum of clinical phenotypes with varying degrees of malformation of the lower body with involvement of structures deriving from all 3 layers of the trilaminar embryo. We review areas of active investigation in the diagnosis, etiology, epidemiology, and treatment of the disease with a focus on underlying genetics. CRS pathobiology is complex and multifactorial with a significant contribution from environmental factors as evidenced in twin studies. Contemporary genomic and genetic investigations in both human primary tissue and murine in vitro and in vivo models implicate various genes associated with caudal differentiation and neural cell migration in embryogenesis. A large number of identified targets center around the metabolic regulation of retinoic acid and its derivatives. Dysregulation of retinoic acid homeostasis has been associated with abnormal embryonic cell migration, differentiation, and organogenesis with resulting malformations and agenesis in both a laboratory and a clinical setting. There appears to be a significant overlap in potential genetic targets with CRS and other developmental syndromes with similar presentations, such as VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities) association. CRS represents a spectrum of caudal developmental abnormalities with treatment options limited to mild and moderate expressions of disease. Continued research is necessary to further clarify mechanisms of disease pathobiology and complex polygenetic and environmental interaction. Despite this, progress has been made in identifying genetic targets and downstream effectors contributing to preclinical and clinical progression.

DiGeorge syndrome chromosome region deletion and duplication: Prenatal genotype-phenotype variability in fetal ultrasound and MRI

OBJECTIVE

The aim of the study was to assess genotype-phenotype correlation of prenatally diagnosed fetal DGS and dup22q11 syndrome by fetal molecular genetic analysis, fetal ultrasound, and/or MRI.

METHODS

In this retrospective consecutive case series, pregnant women were screened for fetal anomalies during a period of 10 years. Fetal genotype was assessed in 72 cases upon the occurrence of five prenatal fetal phenotypic features: cardiac anomalies, hypo/aplastic thymus, craniofacial malformations, urinary abnormalities, or IUGR; genotype-phenotype correlation was tested to potentially improve prenatal diagnosis of fetal DGS and dup22q11 syndrome.

RESULTS

Fetal genotypes of deletions or duplications in proximal clusters of LCR22s (A-B) were associated with fetal cardiac anomalies in combination with hypo/aplastic thymus and craniofacial malformations, suggesting a correlation with deleted HIRA. TOF associated with aplastic thymus in combination with renal defects indicated a relevant correlation with TBX1 deletion. Deletions in central LCR22s (B-D) with the loss of CRKL supposed a trend of genotype-phenotype correlation with fetal urinary abnormalities.

CONCLUSION

Genotype-phenotype correlation might improve prenatal diagnosis of fetal DGS and dup22q11 syndrome. Hence, prenatal screening and counseling is highly enhanced by a combination of fetal molecular genetic analysis, fetal ultrasound, and/or MRI. The implications of these findings remain to be explored.

Congenital nephrotic syndrome associated with 22q11.2 duplication syndrome in a Chinese family and functional analysis of the intronic NPHS1 c. 3286 + 5G > A mutation

Background

Congenital nephrotic syndrome (CNS), which is defined as heavy proteinuria, hypoalbuminemia, hyperlipidemia and edema, is most caused by monogenic defects in structural proteins of the glomerular filtration barrier in the kidneys. 22q11.2 duplication syndrome was a chromosomal disease with variable clinical featuresranging from normal to mental retardation and with congenital defects. Co-occurrence of two genetic disorders in a single patient is rare.

Case presentation

The proband was born at 36 weeks of gestational age spontaneously and weighed 2350 g at birth. Six days after birth, the proband was admitted to our hospital due to fever of 38.5 °C lasting for 6 h. Physical examination at admission time showed dysmorphic features of hypertelorism, palpebral edema, broad nose bridge, upturned nose, dysmorphic auricle, long philtrum, and a thin upper lip. Additionally, we found left wrist drop and bilateral strephexopodia, bilateral knee joint flexion contracture in this patient. A series of indicators were detected and showed abnormalities. Albumin was used to remit the hypoproteinemia and edema. However, the parents refused to accept further therapy and the boy died at age 3 months due to cachexy. To confirm the pathogenesis, genetic analysis were performed and revealed two mutations of NPHS1 gene: Exon18: c.2386G > C; p. (Gly796Arg) inherited from mother, and intron24: c.3286 + 5G > A; p.? inherited from father. And he also had a 22q11.2 duplication which was inherited from his mild affected mother. The pathogenesis of the intronic mutation has been further identified that it can defect alternative splicing of NPHS1.

Conclusions

We present a patient who was caught in congenital nephrotic syndrome and 22q11.2 duplication syndrome simultaneously, emphasizing the importance of new sequencing technology on diagnosis of different genetic disorders.

22q11.2 Microduplication: An Enigmatic Genetic Disorder

Microduplication of 22q11.2 involves having an extra copy at position q11.2 on chromosome 22. Very few cases have been reported but the real incidence may be higher as the absence of obvious clinical signs makes diagnosis difficult. In the cases that are diagnosed, the phenotype is extremely variable. We describe a case of severe micrognathia, cleft palate, and Pierre-Robin sequence. A prenatal ultrasound showed severe micrognathia and subsequent microarray done on amniocentesis revealed the microduplication of 22q11.2, which was confirmed postnatally. Although micrognathia has often been detected in this microduplication, the constellation of these findings has not been previously described.