Case report: Novel variants cause developmental and epileptic encephalopathy in three unrelated families from Mali.

Background And Objectives: Developmental and epileptic encephalopathies (DEEs) are a group of neurological disorders characterized by early-onset seizures that are often resistant to treatment, by electroencephalographic abnormalities, and by developmental delay or regression. Their genetic basis remains largely unelucidated, especially in sub-Saharan Africa (SSA). We investigated the genetic bases of DEE in three Malian families.

Genetic profile of progressive myoclonic epilepsy in Mali reveals novel findings.

Background And Objectives: Progressive myoclonic epilepsy (PME) is a group of neurological disorders characterized by recurrent myoclonic seizures with progressive neurological deterioration. We investigated the genetics of three unrelated patients with PME from Mali, a country in sub-Saharan Africa highly underrepresented in genetic and genomic research.

Methods: Participants were carefully examined and phenotyped.

Exome sequencing reveals genetic heterogeneity in consanguineous Pakistani families with neurodevelopmental and neuromuscular disorders.

There remains a crucial need to address inequalities in genomic research and include populations from low- and middle-income countries (LMIC). Here we present eight consanguineous families from Pakistan, five with neurodevelopmental disorders (NDDs) and three with neuromuscular disorders (NMDs). Affected individuals were clinically characterized, and genetic variants were identified through exome sequencing (ES), followed by family segregation analysis.

AP2A2 mutation and defective endocytosis in a Malian family with hereditary spastic paraplegia.

Hereditary spastic paraplegia (HSP) comprises a large group of neurogenetic disorders characterized by progressive lower extremity spasticity. Neurological evaluation and genetic testing were completed in a Malian family with early-onset HSP. Three children with unaffected consanguineous parents presented with symptoms consistent with childhood-onset complicated HSP.

Biallelic CRELD1 variants cause a multisystem syndrome, including neurodevelopmental phenotypes, cardiac dysrhythmias, and frequent infections.

Purpose: We sought to delineate a multisystem disorder caused by recessive cysteine-rich with epidermal growth factor-like domains 1 (CRELD1) gene variants.

Methods: The impact of CRELD1 variants was characterized through an international collaboration utilizing next-generation DNA sequencing, gene knockdown, and protein overexpression in Xenopus tropicalis, and in vitro analysis of patient immune cells.

Results: Biallelic variants in CRELD1 were found in 18 participants from 14 families.

Sequence variants in different genes underlying Bardet-Biedl syndrome in four consanguineous families.

Background: Bardet-Biedl Syndrome (BBS) is a rare (1:13,500-1-160,000) heterogeneous congenital disorder, characterized by postaxial polydactyly, obesity, hypogonadism, rod-cone dystrophy, cognitive impairment, and renal abnormalities (renal cystic dysplasia, anatomical malformation). To date about twenty-five genes have been identified to cause BBS, which accounts for about 80% of BBS diagnosis.

Methods: In the current study, we have performed mutational screening of four Pakistani consanguineous families (A-D) with clinical manifestation of BBS by microsatellite-based genotyping and whole exome sequencing.

Microinjection of Embryos.

Microinjection is an important technique used to study development in the oocyte and early embryo. In , substances such as DNA, mRNA, and morpholino oligonucleotides have traditionally been injected into , because of their large embryo size and the relatively long time from their fertilization to first division. In the past few decades, has become an important model in developmental biology; it is particularly useful in genetic studies.

Tadpole Craniocardiac Imaging Using Optical Coherence Tomography.

Optical coherence tomography (OCT) imaging can be used to visualize craniocardiac structures in the model system. OCT is analogous to ultrasound, utilizing light instead of sound to create a gray-scale image from the echo time delay of infrared light reflected from the specimen. OCT is a high-speed, cross-sectional, label-free imaging modality, which can outline dynamic in vivo morphology at resolutions approaching histological detail.

Obtaining Eggs.

is a powerful model system for cell and developmental biology in part because frogs produce thousands of eggs and embryos year-round. For cell biological studies, egg extracts can mimic many processes in a cell-free system. For developmental biology, embryos are a premier system, combining cut-and-paste embryology with modern gene manipulation tools.

Expansion of NEUROD2 phenotypes to include developmental delay without seizures.

De novo heterozygous variants in the brain-specific transcription factor Neuronal Differentiation Factor 2 (NEUROD2) have been recently associated with early-onset epileptic encephalopathy and developmental delay. Here, we report an adolescent with developmental delay without seizures who was found to have a novel de novo heterozygous NEUROD2 missense variant, p.(Leu163Pro).

The latest FADS: Functional analysis of GLDN patient variants and classification of GLDN-associated AMC as a type of viable fetal akinesia deformation sequence.

Recessive variants in the GLDN gene, which encodes the gliomedin protein and is involved in nervous system development, have recently been associated with Arthrogryposis Multiplex Congenita (AMC), a heterogenous condition characterized by congenital contractures of more than one joint. Two cohorts of patients with GLDN-associated AMC have previously been described, evolving the understanding of the condition from lethal to survivable with the provision of significant neonatal support. Here, we describe one additional patient currently living with the syndrome, having one novel variant, p.

, a candidate gene for isolated congenital asplenia, is required for pre-rRNA processing and spleen formation in .

A growing number of tissue-specific inherited disorders are associated with impaired ribosome production, despite the universal requirement for ribosome function. Recently, mutations in RPSA, a protein component of the small ribosomal subunit, were discovered to underlie approximately half of all isolated congenital asplenia cases. However, the mechanisms by which mutations in this ribosome biogenesis factor lead specifically to spleen agenesis remain unknown, in part due to the lack of a suitable animal model for study.

CRISPR/Cas9 F0 Screening of Congenital Heart Disease Genes in Xenopus tropicalis.

In the US and Europe, birth defects are the leading cause of infant mortality. Among birth defects, Congenital Heart Disease (CHD) occurs in approximately 8 out of 1000 live births, affects 1.3 million newborns per year worldwide, and has the highest mortality rate.

Visualization and quantification of injury to the ciliated epithelium using quantitative flow imaging and speckle variance optical coherence tomography.

Mucociliary flow is an important defense mechanism in the lung to remove inhaled pathogens and pollutants. Disruption of ciliary flow can lead to respiratory infections. Multiple factors, from drugs to disease can cause an alteration in ciliary flow.

CRISPRscan: designing highly efficient sgRNAs for CRISPR-Cas9 targeting in vivo.

CRISPR-Cas9 technology provides a powerful system for genome engineering. However, variable activity across different single guide RNAs (sgRNAs) remains a significant limitation. We analyzed the molecular features that influence sgRNA stability, activity and loading into Cas9 in vivo.

Uncovering buffered pleiotropy: a genome-scale screen for mel-28 genetic interactors in Caenorhabditis elegans.

mel-28 (maternal-effect-lethal-28) encodes a conserved protein required for nuclear envelope function and chromosome segregation in Caenorhabditis elegans. Because mel-28 is a strict maternal-effect lethal gene, its function is required in the early embryo but appears to be dispensable for larval development. We wanted to test the idea that mel-28 has postembryonic roles that are buffered by the contributions of other genes.

Forward genetics defines Xylt1 as a key, conserved regulator of early chondrocyte maturation and skeletal length.

The long bones of the vertebrate body are built by the initial formation of a cartilage template that is later replaced by mineralized bone. The proliferation and maturation of the skeletal precursor cells (chondrocytes) within the cartilage template and their replacement by bone is a highly coordinated process which, if misregulated, can lead to a number of defects including dwarfism and other skeletal deformities. This is exemplified by the fact that abnormal bone development is one of the most common types of human birth defects.

High-throughput fluorescence-based isolation of live C. elegans larvae.

For the nematode Caenorhabditis elegans, automated selection of animals of specific genotypes from a mixed pool has become essential for genetic interaction or chemical screens. To date, such selection has been accomplished using specialized instruments. However, access to such dedicated equipment is not common.