Publications by authors named "Ethiraj Ravindran"

Disruption of neocortical circuitry and architecture in humans causes numerous neurodevelopmental disorders. Neocortical cytoarchitecture is orchestrated by various transcription factors such as Satb2 that control target genes during strict time windows. In humans, mutations of SATB2 cause SATB2 Associated Syndrome (SAS), a multisymptomatic syndrome involving epilepsy, intellectual disability, speech delay, and craniofacial defects.

View Article and Find Full Text PDF
Article Synopsis
  • - Nucleoporin (NUP) 85 is essential for various cellular processes, and mutations in its gene are linked to multiple human diseases, including steroid-resistant nephrotic syndrome (SRNS).
  • - Recent findings expand the range of disorders associated with NUP85 by identifying variants in individuals with primary autosomal recessive microcephaly (MCPH) and Seckel syndrome (SCKS), revealing a broader impact of NUP85 mutations.
  • - The study demonstrates that certain missense variants diminish cell viability in fibroblasts and may disrupt the structural integrity and interactions of NUP85, highlighting its importance in brain development and function.
View Article and Find Full Text PDF

Collapsin response mediator proteins (CRMPs) are key for brain development and function. Here, we link CRMP1 to a neurodevelopmental disorder. We report heterozygous de novo variants in the gene in three unrelated individuals with muscular hypotonia, intellectual disability, and/or autism spectrum disorder.

View Article and Find Full Text PDF
Article Synopsis
  • Autosomal recessive primary microcephaly (MCPH) is a rare disorder linked to intellectual disability and smaller head size at birth, primarily caused by mutations in the CDK5RAP2 gene.* -
  • The study used two-dimensional gel electrophoresis to analyze protein changes in the cerebral cortices of Cdk5rap2 mutant mice, revealing over 30 proteins affected that are related to brain development processes.* -
  • Findings highlight potential protein candidates that may contribute to the brain abnormalities seen in MCPH3, providing insight into the disorder's underlying mechanisms.*
View Article and Find Full Text PDF

RhoGTPase regulators play a key role in the development of the nervous system, and their dysfunction can result in brain malformation and associated disorders. Several guanine nucleotide exchange factors (GEF) have been linked to neurodevelopmental disorders. In line with this, ARHGEF17 has been recently linked as a risk gene to intracranial aneurysms.

View Article and Find Full Text PDF
Article Synopsis
  • Mutations in the PTRH2 gene cause a severe disease in infants that affects multiple body systems and leads to neurologic, endocrine, and pancreatic issues.
  • Researchers created specific mouse models to study how the lack of PTRH2 affects cerebellar development and found that general PTRH2 knockout mice experienced severe growth issues and early death, while Purkinje cell-specific knockouts survived longer but developed significant cerebellar problems.
  • The study highlights that PTRH2 is crucial for the maturation and survival of Purkinje cells, as its absence disrupts a key signaling pathway (mTOR), leading to cell atrophy and the characteristic symptoms observed in affected patients.
View Article and Find Full Text PDF

Primary autosomal recessive microcephaly and Seckel syndrome spectrum disorders (MCPH-SCKS) include a heterogeneous group of autosomal recessive inherited diseases characterized by primary (congenital) microcephaly, the absence of visceral abnormalities, and a variable degree of cognitive impairment, short stature and facial dysmorphism. Recently, biallelic variants in the nuclear pore complex (NPC) component nucleoporin 85 gene (NUP85) were reported to cause steroid-resistant nephrotic syndrome (SRNS). Here, we report biallelic variants in NUP85 in two pedigrees with an MCPH-SCKS phenotype spectrum without SRNS, thereby expanding the phenotypic spectrum of NUP85-linked diseases.

View Article and Find Full Text PDF

-methyladenosine (mA) is emerging as a vital factor regulating neural differentiation. Here, we report that deficiency of , a novel cause of a neurodevelopmental disorder we identified recently, impairs neurogenesis, neurite outgrowth, and synaptic formation by regulating mA methylation. knockout decreases expression of and total mA level significantly in the cerebral cortex.

View Article and Find Full Text PDF
Article Synopsis
  • The MCM complex, particularly components 2, 4, 5, and 6, is linked to neurodevelopmental diseases such as microcephaly and intellectual disability due to its role in DNA replication, especially in neural stem cells.
  • Whole-exome sequencing identified a specific mutation (c.793G>A/p.A265T) in the MCM7 gene that correlates with autosomal recessive primary microcephaly and severe intellectual disability in a family with three affected members.
  • The study also demonstrated that MCM7 expression is higher during early brain development and in undifferentiated stem cells, suggesting its critical role in nervous system development, with downregulation leading
View Article and Find Full Text PDF

Biallelic mutations in the cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2 cause autosomal recessive primary microcephaly type 3 (MCPH3). MCPH is characterized by intellectual disability and microcephaly at birth, classically without further organ involvement. Only recently, congenital cataracts were reported in four patients of one pedigree with MCPH3.

View Article and Find Full Text PDF
Article Synopsis
  • Mid-hindbrain malformations can arise from disruptions in gene expression during embryo development, affecting brain structure formation.
  • A specific mutation in the ARHGEF2 gene was found to cause intellectual disabilities and brain malformations in a Kurdish-Turkish family, indicating its critical role in brain development.
  • Research demonstrated that the loss of ARHGEF2 disrupts cell differentiation and migration, leading to distinct brain development issues that were also observed in mouse models.
View Article and Find Full Text PDF

Autosomal recessive primary microcephaly (MCPH) is a rare neurodevelopmental disorder characterized by a pronounced reduction of brain volume and intellectual disability. A current model for the microcephaly phenotype invokes a stem cell proliferation and differentiation defect, which has moved the disease into the spotlight of stem cell biology and neurodevelopmental science. Homozygous mutations of the Cyclin-dependent kinase-5 regulatory subunit-associated protein 2 gene CDK5RAP2 are one genetic cause of MCPH.

View Article and Find Full Text PDF

Biallelic mutations in the gene encoding centrosomal CDK5RAP2 lead to autosomal recessive primary microcephaly (MCPH), a disorder characterized by pronounced reduction in volume of otherwise architectonical normal brains and intellectual deficit. The current model for the microcephaly phenotype in MCPH invokes a premature shift from symmetric to asymmetric neural progenitor-cell divisions with a subsequent depletion of the progenitor pool. The isolated neural phenotype, despite the ubiquitous expression of CDK5RAP2, and reports of progressive microcephaly in individual MCPH cases prompted us to investigate neural and non-neural differentiation of Cdk5rap2-depleted and control murine embryonic stem cells (mESC).

View Article and Find Full Text PDF

The autosomal recessive immunodeficiency-centromeric instability-facial anomalies syndrome (ICF) is characterized by immunodeficiency, developmental delay, and facial anomalies. ICF2, caused by biallelic ZBTB24 gene mutations, is acknowledged primarily as an isolated B-cell defect. Here, we extend the phenotype spectrum by describing, in particular, for the first time the development of a combined immune defect throughout the disease course as well as putative autoimmune phenomena such as granulomatous hepatitis and nephritis.

View Article and Find Full Text PDF

Background: Autosomal recessive primary microcephaly (MCPH) is a rare neurodevelopmental disease with severe microcephaly at birth due to a pronounced reduction in brain volume and intellectual disability. Biallelic mutations in the WD repeat-containing protein 62 gene WDR62 are the genetic cause of MCPH2. However, the exact underlying pathomechanism of MCPH2 remains to be clarified.

View Article and Find Full Text PDF

Several subtypes of melanopsin-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs) have been reported. The M1 type of ipRGCs exhibit distinct properties compared with the remaining (non-M1) cells. They differ not only in their soma size and dendritic arbor, but also in their physiological properties, projection patterns, and functions.

View Article and Find Full Text PDF