Altered functional brain dynamics in chromosome 22q11.2 deletion syndrome during facial affect processing

Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a multisystem disorder associated with multiple congenital anomalies, variable medical features, and neurodevelopmental differences resulting in diverse psychiatric phenotypes, including marked deficits in facial memory and social cognition. Neuroimaging in individuals with 22q11.2DS has revealed differences relative to matched controls in BOLD fMRI activation during facial affect processing tasks. However, time-varying interactions between brain areas during facial affect processing have not yet been studied with BOLD fMRI in 22q11.2DS. We applied constrained principal component analysis to identify temporally overlapping brain activation patterns from BOLD fMRI data acquired during an emotion identification task from 58 individuals with 22q11.2DS and 58 age-, race-, and sex-matched healthy controls. Delayed frontal-motor feedback signals were diminished in individuals with 22q11.2DS, as were delayed emotional memory signals engaging amygdala, hippocampus, and entorhinal cortex. Early task-related engagement of motor and visual cortices and salience-related insular activation were relatively preserved in 22q11.2DS. Insular activation was associated with task performance within the 22q11.2DS sample. Differences in cortical surface area, but not cortical thickness, showed spatial alignment with an activation pattern associated with face processing. These findings suggest that relative to matched controls, primary visual processing and insular function are relatively intact in individuals with 22q11.22DS, while motor feedback, face processing, and emotional memory processes are more affected. Such insights may help inform potential interventional targets and enhance the specificity of neuroimaging indices of cognitive dysfunction in 22q11.2DS.

Case Report: Autoimmune Psychosis in Chromosome 22q11.2 Deletion Syndrome

Chromosome 22q11.2 deletion syndrome (22q11DS) is characterized by congenital cardiac abnormalities, hypoplastic thymus, palatal abnormalities, and hypocalcemia, although other clinical features are frequent such as autoimmune and psychiatric disorders. One-third of the patients have psychotic disorders, frequently followed by developmental regression and long-term cognitive disturbances. Despite humoral and cellular immunodeficiency are common in 22q11DS, it is associated with an increased prevalence of autoimmune disorders such as idiopathic thrombocytopenic purpura and juvenile idiopathic arthritis, likely due to immune dysregulations associated with thymic abnormalities, which plays a major role in self-tolerance. We report an unique case of a 14-year-old girl with 22q11DS that presented with subacute psychotic symptoms, intolerance to antipsychotics, CSF pleocytosis, and EEG abnormalities, that was successfully treated with empiric immunotherapy after fulfilling criteria for probable seronegative autoimmune encephalitis and probable autoimmune psychosis. The autoimmune etiology of these clinical features of 22q11DS has never been postulated despite the predisposition of this syndrome to present autoimmune disorders. We suggest the systematic evaluation with serum and CSF neuronal antibodies, MRI, and EEG of patients with 22q11DS that develop subacute psychotic symptoms or rapidly progressive cognitive decline. Early immunomodulatory therapies should be carefully considered if criteria of probable autoimmune psychosis or possible autoimmune encephalitis are fulfilled, as it may prevent long-term disabilities. Further studies are required to assess the autoimmune origin of psychosis and cognitive impairment associated with 22q11DS.

Concurrent Scoliosis and Dentofacial Anomaly: A Case Report

The relationship between scoliosis, dentofacial anomaly, and malocclusion is poorly understood. We report a novel and complex pediatric case of concurrent juvenile scoliosis, dentofacial anomaly, and malocclusion, successfully treated and managed by an interdisciplinary hospital team over a 15-year period. The degree of severity of the scoliosis and dentofacial anomaly necessitates surgical intervention. Successful orthopedic surgical procedures have improved the patient’s quality of life. Future surgical correction of the dentofacial anomaly and malocclusion is necessary to improve the patient’s condition from psychosocial, aesthetic, and functional standpoints. The patient’s condition is characterized by multiple congenital abnormalities, developmental delay, seizure disorder, juvenile scoliosis, and dentofacial anomaly with malocclusion. Intriguingly, a unifying diagnosis for the patient’s condition could not be confirmed despite the indication of a syndromic cause. The collection of characteristics is suggestive of the chromosome 22q11.2 deletion syndromes (including velocardiofacial syndrome [VCFS] or DiGeorge syndrome) as possible genetic causes. Clinical genetics testing was unable to establish a diagnosis of chromosome 22q11.2 deletion, VCFS or DiGeorge syndrome. Further investigation of the genotype-phenotype relationships of scoliosis, dentofacial anomaly, and malocclusion is required to improve medical knowledge, diagnostic capability, and patient care, specifically relating to cases of undiagnosed diseases. Future research utilizing next-generation sequencing techniques is necessary to aim for precise genetic diagnosis, including knowledge of the underlying cellular and molecular mechanisms, for the development of the potential of therapeutic approaches targeting gene repair.

DiGeorge syndrome presenting with seizure in neonatal period: a case report

DiGeorge syndrome is caused by a micro-deletion of chromosome 22q11.2 that disrupts development of the third and fourth pharyngeal pouches during early embryogenesis. Other structures forming at the same period are also frequently affected. So, the phenotypic spectrum shows a wide variability. In this case report, we describe a 1-month and 24-day old male child who presented with history of recurrent afebrile seizure and noisy breathing since early neonatal period. He had history of repeated chest infections. On examination, patient had stridor, facial dysmorphism, pectus excavatum and clinical features of pneumonia. Investigations revealed hypocalcaemia, hypoparathyroidism, consolidation on X-ray chest and cellular immunodeficiency. Echocardiography findings were normal. Fluorescent in situ hybridization (FISH) was performed which confirmed the diagnosis 22q11.2 deletion. Birdem Med J 2021; 11(2): 128-132

Tbx1, a 22q11.2-encoded gene, is a link between alterations in fimbria myelination and cognitive speed in mice

Copy number variants (CNVs) have provided a reliable entry point to identify structural correlates of atypical cognitive development. Hemizygous deletion of human chromosome 22q11.2 is associated with impaired cognitive function; however, the mechanisms by which numerous genes encoded in this CNV contribute to cognitive deficits via diverse structural alterations in the brain remain unclear. This study aimed to determine the cellular basis of the link between alterations in brain structure and cognitive functions in a mouse model. The heterozygosity of Tbx1, a 22q11.2 gene, altered the composition of myelinated axons in the fimbria, reduced oligodendrocyte production capacity, and slowed the acquisition of spatial memory and cognitive flexibility. Our findings provide a cellular basis for specific cognitive dysfunctions that occur in patients with loss-of-function TBX1 variants and 22q11.2 hemizygous deletion.

The differential expression and regulatory networks of ceRNAs in umbilical cord blood sample of chromosome 22q11.2 deletion syndrome

Background: Chromosome 22q11.2 deletion (CH22qD) syndrome is the most common human deletion syndrome. Competing endogenous RNAs (ceRNAs) have miRNA binding sites that are capable of competitively binding miRNAs and inhibiting miRNA regulation of target genes. Results: We identified differently expressed miRNAs, circRNAs, lncRNAs and mRNAs of CH22qD, and we analysed the results by using GO analysis, KEGG pathway analysis and network regulation analysis. Conclusions: These analyses may predict the effects of chromosomal microdeletions.