Clinico-biological refinement of BCL11B-related disorder and identification of an episignature: A series of 20 unreported individuals

PURPOSE

BCL11B-related disorder (BCL11B-RD) arises from rare genetic variants within the BCL11B gene, resulting in a distinctive clinical spectrum encompassing syndromic neurodevelopmental disorder, with or without intellectual disability, associated with facial features and impaired immune function. This study presents an in-depth clinico-biological analysis of 20 newly reported individuals with BCL11B-RD, coupled with a characterization of genome-wide DNA methylation patterns of this genetic condition.

METHODS

Through an international collaboration, clinical and molecular data from 20 individuals were systematically gathered, and a comparative analysis was conducted between this series and existing literature. We further scrutinized peripheral blood DNA methylation profile of individuals with BCL11B-RD, contrasting them with healthy controls and other neurodevelopmental disorders marked by established episignature.

RESULTS

Our findings unveil rarely documented clinical manifestations, notably including Rubinstein-Taybi-like facial features, craniosynostosis, and autoimmune disorders, all manifesting within the realm of BCL11B-RD. We refine the intricacies of T cell compartment alterations of BCL11B-RD, revealing decreased levels naive CD4+ T cells and recent thymic emigrants while concurrently observing an elevated proportion of effector-memory expressing CD45RA CD8+ T cells (TEMRA). Finally, a distinct DNA methylation episignature exclusive to BCL11B-RD is unveiled.

CONCLUSION

This study serves to enrich our comprehension of the clinico-biological landscape of BCL11B-RD, potentially furnishing a more precise framework for diagnosis and follow-up of individuals carrying pathogenic BCL11B variant. Moreover, the identification of a unique DNA methylation episignature offers a valuable diagnosis tool for BCL11B-RD, thereby facilitating routine clinical practice by empowering physicians to reevaluate variants of uncertain significance within the BCL11B gene.

Lessons from two series by physicians and caregivers' self-reported data in DDX3X-related disorders

INTRODUCTION AND METHODS

We report two series of individuals with DDX3X variations, one (48 individuals) from physicians and one (44 individuals) from caregivers.

RESULTS

These two series include several symptoms in common, with fairly similar distribution, which suggests that caregivers' data are close to physicians' data. For example, both series identified early childhood symptoms that were not previously described: feeding difficulties, mean walking age, and age at first words.

DISCUSSION

Each of the two datasets provides complementary knowledge. We confirmed that symptoms are similar to those in the literature and provides more details on feeding difficulties. Caregivers considered that the symptom attention-deficit/hyperactivity disorder were most worrisome. Both series also reported sleep disturbance. Recently, anxiety has been reported in individuals with DDX3X variants. We strongly suggest that attention-deficit/hyperactivity disorder, anxiety, and sleep disorders need to be treated.

Molecular Diagnosis of Primary Cardiomyopathy in 231 Unrelated Pediatric Cases by Panel-Based Next-Generation Sequencing: A Major Focus on Five Carriers of Biallelic TNNI3 Pathogenic Variants

BACKGROUND AND OBJECTIVE

Pediatric cardiomyopathies are clinically heterogeneous heart muscle disorders associated with significant morbidity and mortality for which substantial evidence for a genetic contribution was previously reported. We present a detailed molecular investigation of a cohort of 231 patients presenting with primary cardiomyopathy below the age of 18 years.

METHODS

Cases with pediatric cardiomyopathies were analyzed using a next-generation sequencing (NGS) workflow based on a virtual panel including 57 cardiomyopathy-related genes.

RESULTS

This molecular approach led to the identification of 69 cases (29.9% of the cohort) genotyped as a carrier of at least one pathogenic or likely pathogenic variant. Fourteen patients were carriers of two mutated alleles (homozygous or compound heterozygous) on the same cardiomyopathy-related gene, explaining the severe clinical disease with early-onset cardiomyopathy. Homozygous TNNI3 pathogenic variants were detected for five unrelated neonates (2.2% of the cohort), with four of them carrying the same truncating variant, i.e. p.Arg69Alafs*8.

CONCLUSIONS

Our study confirmed the importance of genetic testing in pediatric cardiomyopathies. Discovery of novel pathogenic variations is crucial for clinical management of affected families, as a positive genetic result might be used by a prospective parent for prenatal genetic testing or in the process of pre-implantation genetic diagnosis.

Vesiclemia: counting on extracellular vesicles for glioblastoma patients

Although rare, glioblastoma is a devastating tumor of the central nervous system characterized by a poor survival and an extremely dark prognosis, making its diagnosis, treatment, and monitoring highly challenging. Numerous studies have highlighted extracellular vesicles (EVs) as key players of tumor growth, invasiveness, and resistance, as they carry oncogenic material. Moreover, EVs have been shown to communicate locally in a paracrine way but also at remote throughout the organism. Indeed, recent reports demonstrated the presence of brain tumor-derived EVs into body fluids such as plasma and cerebrospinal fluid. Fluid-associated EVs have indeed been suspected to reflect quantitative and qualitative information about the status and fate of the tumor and can potentially act as a resource for noninvasive biomarkers that might assist in diagnosis, treatment, and follow-up of glioblastoma patients. Here, we coined the name vesiclemia to define the concentration of plasmatic EVs, an intuitive term to be directly transposed in the clinical jargon.