Actionable Genomics in Clinical Practice: Paradigmatic Case Reports of Clinical and Therapeutic Strategies Based upon Genetic Testing

[Genetic Diagnostics in Everyday Clinical Practice in Child and Adolescent Psychiatry: Indications, Framework Conditions, Hurdles, and Proposed Solutions]

Genetic Diagnostics in Everyday Clinical Practice in Child and Adolescent Psychiatry: Indications, Framework Conditions, Hurdles, and Proposed Solutions Abstract: Health insurance covers medically necessary genetic testing in Germany. Diagnostic genetic testing has become increasingly important for child and adolescent psychiatry (CAP), reflected by the rising number of national guidelines relevant to CAP, including genetic testing in the recommended diagnostic work-up. However, implementation of theses guidelines in routine clinical care is lacking. This article provides a concise overview of the relevance of genetic testing in CAP-related national guidelines. It outlines the legal and financial framework for genetic testing in Germany. Furthermore, it points out barriers to implementation and offers potential solutions. It then provides examples from clinical practice highlighting the potential benefits patients and their family members might have from receiving a genetic diagnosis. The article closes by outlining future CAP-relevant areas in which genetic testing may become clinically relevant.

DLG2 intragenic exonic deletions reinforce the link to neurodevelopmental disorders and suggest a potential association with congenital anomalies and dysmorphism

PURPOSE

Multiple studies suggest an association between DLG2 and neurodevelopmental disorders and indicate the haploinsufficiency of this gene; however, few cases have been thoroughly described. We performed additional studies to confirm this clinical association and DLG2 haploinsufficiency.

METHODS

Chromosomal microarray analysis was performed on 11,107 patients at the Cytogenetics Laboratory at the University of Alabama at Birmingham. The Database of Genomic Variants-Gold Standard Variants and the Genome Aggregation Database were selected for the association analysis. Fifty-nine patients from the literature and DECIPHER, all having DLG2 intragenic deletions, were included for comprehensive analysis of the distribution of these deletions.

RESULTS

A total of 13 patients with DLG2 intragenic deletions, from 10 families in our cohort, were identified. Nine of 10 probands presented with clinical features of neurodevelopmental disorders. Congenital anomalies and dysmorphism were common in our cohort of patients. Association analysis showed that the frequency of DLG2 deletions in our cohort is significantly higher than those in the Database of Genomic Variants-Gold Standard Variants and the Genome Aggregation Database. Most of DLG2 intragenic deletions identified in 69 unrelated patients from our cohort, the literature, and DECIPHER map to the 5' region of the gene, with a hotspot centered around HPin7, exon 8, and HPin8.

CONCLUSION

Our findings reinforce the link between DLG2 intragenic deletions and neurodevelopmental disorders, strongly support the haploinsufficiency of this gene, and indicate that these deletions might also have an association with congenital anomalies and dysmorphism.

Attitudes towards genetic testing: The role of genetic literacy, motivated cognition, and socio-demographic characteristics

Understanding reasons for why people choose to have or not to have a genetic test is essential given the ever-increasing use of genetic technologies in everyday life. The present study explored the multiple drivers of people's attitudes towards genetic testing. Using the International Genetic Literacy and Attitudes Survey (iGLAS), we collected data on: (1) willingness to undergo testing; (2) genetic literacy; (3) motivated cognition; and (4) demographic and cultural characteristics. The 37 variables were explored in the largest to-date sample of 4311 participants from diverse demographic and cultural backgrounds. The results showed that 82% of participants were willing to undergo genetic testing for improved treatment; and over 73%-for research. The 35 predictor variables together explained only a small proportion of variance: 7%-in the willingness to test for Treatment; and 6%-for Research. The strongest predictors of willingness to undergo genetic testing were genetic knowledge and deterministic beliefs. Concerns about data misuse and about finding out unwanted health-related information were weakly negatively associated with willingness to undergo genetic testing. We also found some differences in factors linked to attitudes towards genetic testing across the countries included in this study. Our study demonstrates that decision-making regarding genetic testing is influenced by a large number of potentially interacting factors. Further research into these factors may help consumers to make decisions regarding genetic testing that are right for their specific circumstances.

Spanish mental health residents' perspectives about residency education on the genetics of psychiatric disorders: A cross-sectional survey

Despite compelling evidence that some patients with a psychiatric diagnosis could benefit from genetic assessment, genetic testing for psychiatric patients is underutilized. Few studies have reported psychiatric genetics training for mental health specialists, and such research is especially lacking in Spain. We aimed to gather the opinions of Spanish mental health residents, including resident intern nurses (RINs), doctors (RIDs) and psychologists (RIPs). A short survey was prepared by an expert team and distributed to all mental health residency centers in Spain during the first semester of 2021. Of the 2028 residents, 18% responded. Participants were mainly females (71%), in their first year of residency (37%) and within the 27-31-year age range. While participants received little theoretical (13.4%) and practical (4.6%) training on average, RIDs had the most affirmative responses. Notably, RINs and RIDs were interested in genetics during residency (>40%) and strongly believed (85.0%) that genetics training using both theoretical and practical methodologies should be incorporated into residency training. However, RIPs were less interested (20%), and only 60% believed that genetics training should be incorporated. Spanish mental health residents, although interested in genetics in psychiatry, receive little training on this topic. They strongly believe that genetics training using theoretical and practical methodologies should be incorporated.

16p11.2 Microduplication Syndrome with Increased Fluid in the Cisterna: Coincidence or Phenotype Extension?

We report the first case of a child with 16p11.2 microduplication syndrome with increased fluid in the cisterna magna seen on magnetic resonance imaging (MRI). This finding may correspond to a Blake's Pouch Cyst (BPC) or a Mega Cisterna Magna (MCM), being impossible to differentiate through image examination. The molecular duplication was diagnosed using chromosomal microarray analysis with single nucleotide polymorphism (SNP). We review the clinical and neuroimaging features in published case reports in order to observe the findings described in the literature so far and present a skull three-dimensional model to contribute to a better understanding. Despite the variable expressivity of the syndrome being well known, there is no case described in the available literature that mentions the association of 16p11.2 microduplication and the presence of BPC or MCM seen in neuroimaging exams. This finding may represent an extension of the phenotype not yet reported or may present itself as a coincidence in a child with various malformations.

Diagnostic yield and clinical impact of chromosomal microarray analysis in autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is characterized by high heritability estimates and recurrence rates; its genetic underpinnings are very heterogeneous and include variable combinations of common and rare variants. Array-comparative genomic hybridization (aCGH) offers significant sensitivity for the identification of copy number variants (CNVs), which can act as susceptibility or causal factors for ASD.

METHODS

The aim of this study was to evaluate both diagnostic yield and clinical impact of aCGH in 329 ASD patients of Italian descent.

RESULTS

Pathogenic/likely pathogenic CNVs were identified in 50/329 (15.2%) patients, whereas 89/329 (27.1%) carry variants of uncertain significance. The 10 most enriched gene sets identified by Gene Ontology Enrichment Analysis are primarily involved in neuronal function and synaptic connectivity. In 13/50 (26.0%) patients with pathogenic/likely pathogenic CNVs, the outcome of array-CGH led to the request of 25 additional medical exams which would not have otherwise been prescribed, mainly including brain MRI, EEG, EKG, and/or cardiac ultrasound. A positive outcome was obtained in 12/25 (48.0%) of these additional tests.

CONCLUSIONS

This study confirms the satisfactory diagnostic yield of aCGH, underscoring its potential for better, more in-depth care of children with autism when genetic results are analyzed also with a focus on patient management.

From Genes to Therapy in Autism Spectrum Disorder

In recent years, findings from genetic and other biological studies are starting to reveal the role of various molecular mechanisms that contribute to the etiology of ASD [...]

Yield of array-CGH analysis in Tunisian children with autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with strong genetic underpinnings. Microarray-based comparative genomic hybridization (aCGH) technology has been proposed as a first-level test in the genetic diagnosis of ASD and of neurodevelopmental disorders in general.

METHODS

We performed aCGH on 98 Tunisian children (83 boys and 15 girls) diagnosed with ASD according to DSM-IV criteria.

RESULTS

"Pathogenic" or "likely pathogenic" copy number variants (CNVs) were detected in 11 (11.2%) patients, CNVs of "uncertain clinical significance" in 26 (26.5%), "likely benign" or "benign" CNVs were found in 37 (37.8%) and 24 (24.5%) patients, respectively. Gene set enrichment analysis involving genes spanning rare "pathogenic," "likely pathogenic," or "uncertain clinical significance" CNVs, as well as SFARI database "autism genes" in common CNVs, detected eight neuronal Gene Ontology classes among the top 10 most significant, including synapse, neuron differentiation, synaptic signaling, neurogenesis, and others. Similar results were obtained performing g: Profiler analysis. Neither transcriptional regulation nor immune pathways reached significance.

CONCLUSIONS

aCGH confirms its sizable diagnostic yield in a novel sample of autistic children from North Africa. Recruitment of additional families is under way, to verify whether genetic contributions to ASD in the Tunisian population, differently from other ethnic groups, may involve primarily neuronal genes, more than transcriptional regulation and immune-related pathways.

Developing Gene-Based Personalised Interventions in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with onset in early childhood [...]