Genotype-phenotype correlation in contactin-associated protein-like 2 (CNTNAP-2) developmental disorder

The neurobiology and immunology of CASPR2-associated neurological disorders

CASPR2-associated neurological disorders encompass a wide clinical spectrum broadly divided into overlapping three autoimmune syndromes: CASPR2 limbic encephalitis, Morvan syndrome, and Isaacs syndrome. CASPR2 is a neuronal protein expressed at different sites in the central and peripheral nervous system and has a variety of roles and functions regarding neuronal excitability, synaptic plasticity, and homeostasis of inhibitory networks, most of which are only partially understood. CASPR2 antibodies have various pathogenic effects including internalization of CASPR2, disruption of protein-protein interactions, and, possibly, complement activation. Their pathogenic effect is well demonstrated in the limbic encephalitis phenotype, but the role of pathogenic antibodies in the development of other clinical manifestations is less clear. CASPR2 limbic encephalitis also differ from the other CASPR2-associated disorders in regard to HLA allele and paraneoplastic associations, suggesting it has immunological mechanisms distinct from the other clinical forms. Future studies are needed to better understand how the immunological alterations lead to the different phenotypes associated with CASPR2 antibodies.

Exploring the clinical spectrum of CNTNAP2-related neurodevelopmental disorders: A case series and a literature appraisal

Biallelic pathogenic variants in CNTNAP2, a gene encoding the contactin-associated protein-like 2, have been reported in patients with various clinical presentations including intellectual disability (ID), autistic spectrum disorders (ASD), psychiatric disorders, and focal epilepsy rarely associated to focal cortical dysplasia. We report four children carrying novel biallelic CNTNAP2 pathogenic variants. They present global developmental delay, psychiatric disorders, and focal epilepsy. All patients displayed brain MRI abnormalities consistent with focal temporal dysplasia. One patient had a temporal resection before the availability of genetic testing. Focal cortical dysplasia represents a frequent finding related to focal refractory epilepsy in CNTNAP2 affected patients, and surgery seems to be ineffective in this setting. The genetic testing could therefore be impactful on treatment choices in refractory focal epilepsies.

Decoding the genetic landscape of autism: A comprehensive review

BACKGROUND

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by heterogeneous symptoms and genetic underpinnings. Recent advancements in genetic and epigenetic research have provided insights into the intricate mechanisms contributing to ASD, influencing both diagnosis and therapeutic strategies.

AIM

To explore the genetic architecture of ASD, elucidate mechanistic insights into genetic mutations, and examine gene-environment interactions.

METHODS

A comprehensive systematic review was conducted, integrating findings from studies on genetic variations, epigenetic mechanisms (such as DNA methylation and histone modifications), and emerging technologies [including Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 and single-cell RNA sequencing]. Relevant articles were identified through systematic searches of databases such as PubMed and Google Scholar.

RESULTS

Genetic studies have identified numerous risk genes and mutations associated with ASD, yet many cases remain unexplained by known factors, suggesting undiscovered genetic components. Mechanistic insights into how these genetic mutations impact neural development and brain connectivity are still evolving. Epigenetic modifications, particularly DNA methylation and non-coding RNAs, also play significant roles in ASD pathogenesis. Emerging technologies like CRISPR-Cas9 and advanced bioinformatics are advancing our understanding by enabling precise genetic editing and analysis of complex genomic data.

CONCLUSION

Continued research into the genetic and epigenetic underpinnings of ASD is crucial for developing personalized and effective treatments. Collaborative efforts integrating multidisciplinary expertise and international collaborations are essential to address the complexity of ASD and translate genetic discoveries into clinical practice. Addressing unresolved questions and ethical considerations surrounding genetic research will pave the way for improved diagnostic tools and targeted therapies, ultimately enhancing outcomes for individuals affected by ASD.

Screening of co-expressed genes in hypopharyngeal carcinoma with esophageal carcinoma based on RNA sequencing and Clinical Research

To explore the hub comorbidity genes and potential pathogenic mechanisms of hypopharyngeal carcinoma with esophageal carcinoma, and evaluate their diagnostic value for hypopharyngeal carcinoma with co-morbid esophageal carcinoma. We performed gene sequencing on tumor tissues from 6 patients with hypopharyngeal squamous cell carcinoma with esophageal squamous cell carcinoma (hereafter referred to as "group A") and 6 patients with pure hypopharyngeal squamous cell carcinoma (hereafter referred to as "group B"). We analyzed the mechanism of hub genes in the development and progression of hypopharyngeal squamous cell carcinoma with esophageal squamous cell carcinoma through bioinformatics, and constructed an ROC curve and Nomogram prediction model to analyze the value of hub genes in clinical diagnosis and treatment. 44,876 genes were sequenced in 6 patients with group A and 6 patients with group B. Among them, 76 genes showed significant statistical differences between the group A and the group B.47 genes were expressed lower in the group A than in the group B, and 29 genes were expressed higher. The top five hub genes were GABRG2, CACNA1A, CNTNAP2, NOS1, and SCN4B. GABRG2, CNTNAP2, and SCN4B in the hub genes have high diagnostic value in determining whether hypopharyngeal carcinoma patients have combined esophageal carcinoma (AUC: 0.944, 0.944, 0.972). These genes could possibly be used as potential molecular markers for assessing the risk of co-morbidity of hypopharyngeal carcinoma combined with esophageal carcinoma.

Novel and known minor alleles of CNTNAP2 gene variants are associated with comorbidity of intellectual disability and epilepsy phenotypes: a case-control association study reveals potential biomarkers

BACKGROUND

Neurodevelopmental disorders are heterogeneous due to underlying multiple shared genetic pathways and risk factors. Intellectual disability, epilepsy and autism spectrum disorder phenotypes overlap which indicates the diverse effects of common genes. Recent studies suggested the probable contribution of CNTNAP2 gene polymorphisms to the comorbidity of these neurological conditions.

METHODS AND RESULTS

This study was conducted to investigate the role of CNTNAP2 polymorphisms rs147815978 (G>T) and rs2710102 (A>G) as a risk factor for comorbidity of intellectual disability and epilepsy in a group of 345 individuals including 170 patients and 175 healthy controls recruited from various ethnic groups of Pakistani population. Our case-control study group was genotyped by tetra primer ARMS-PCR technique and results were analysed to know the effects of CNTNAP2 rs147815978 (G>T) and rs2710102 (A>G) polymorphisms in the group. The frequency of risk allele T (rs147815978) and risk allele G (rs2710102) for homozygous recessive genotypes (TT/GG) in our study group was 36.47% while odds ratios for risk allele T (rs147815978) was 5.45 (3.90-7.61: 95% CI, P = 0.000) and that for risk allele G (rs2710102) was 2.39 (1.76-3.24: 95% CI, P = 0.0001). Homozygous recessive genotypes (TT/GG) appeared only in cases and not in control group which indicated these as suspected risk genotypes and the significant association (p < 0.05%) of CNTNAP2 gene polymorphisms rs147815978 (G>T) and rs2710102 (A>G) with co-occurrence of intellectual disability and epilepsy phenotypes in our study group which is in HWE (χ2 = 174, P < 0.0001). Logistic regression analysis shows additive (p < 0.0001) and multiplicative (p < 0.001) models which confirms significant association of both the polymorphisms in our data, which are closely located on same haplotype (D' = - 0.168).

CONCLUSIONS

We propose that CNTNAP2 rs147815978 (G>T) and rs2710102 (A>G) polymorphisms are possible risk loci for overlapping neurodevelopmental disorders in Pakistani population. We propose the role of a previously reported common SNP rs2710102 (A>G) with a rarely reported novel SNP rs147815978 (G>T) for CNTNAP2 gene association with neurodevelopmental disorders in our data. Our study has expanded the knowledge of CNTNAP2 gene polymorphisms as probable biomarkers for susceptibility of co-occurrence of intellectual disability and epilepsy phenotypes in Pakistani population. We hope that our study will open new horizons of CNTNAP2 gene variants research to cure the neurological conditions in Pakistani population where consanguinity is a tradition and prevalence of neurodevelopmental disorders has increased from 1 to 2% during last 5 years.