Researchers at the Icahn School of Medicine at Mount Sinai in New York have identified and described a previously unknown recessive neurodevelopmental disorder (NDD) that appears to be the most prevalent ever discovered. The condition is caused by changes in a small noncoding gene called RNU2-2. It is estimated to affect thousands of individuals in the United States and account for about 10% of all recessive NDD cases with a known genetic cause.

The work was done in collaboration with U.S. collaborators in the Undiagnosed Diseases Network led by colleagues at Stanford University and international collaborators in the United Kingdom, the Netherlands, Belgium, and Italy. The findings, published in the March 30 issue of Nature Genetics, provide long-awaited answers for many families and may inform future drug development.

The team found that the disorder is caused by a near-complete absence of a molecule called U2-2 RNA, which is produced by the RNU2-2 gene. Children with the condition typically inherit one altered copy of the gene from each parent, although sometimes changes arise spontaneously by genetic mutation. While the parents are unaffected, the combined effect on both copies of the gene in their children leads to disrupted brain development in their child.

Linking epigenetics and metabolism in neurogenesis!

Epigenetic regulation and metabolism are tightly coordinated during progenitor cell growth but the processes linking this crosstalk is not well understood.

The researchers examined in neural stem cells the role of PHF8, a histone demethylase whose mutations are linked to Siderius-Hamel syndrome, a rare neurodevelopmental disorder.

The authors show that PHF8 regulates neural progenitor proliferation by coordinating epigenetic and metabolic programs and drives serine biosynthesis by maintaining chromatin accessibility of serine synthesis genes.

They also demonstrate that loss of PHF8 disrupts metabolism, autophagy, and vesicle formation and its deficiency leads to DNA damage and halts neurogenesis in vivo. sciencenewshighlights ScienceMission https://sciencemission.com/Epigenetic-regulation-of-serine-biosynthesis

Progenitor proliferation during neurodevelopment requires tight coordination of epigenetic regulation and metabolism. However, the crosstalk between these processes remains poorly understood. To investigate this, we examine in neural stem cells the role of PHF8, a histone demethylase whose mutations are linked to Siderius-Hamel syndrome, a rare neurodevelopmental disorder. Through an integrated multi-omics approach — combining transcriptomics, epigenomics, and metabolomics — we identify PHF8 as a key driver of the serine biosynthesis pathway, safeguarding the intracellular serine pool essential for neural progenitor proliferation. PHF8 fine-tunes chromatin accessibility at promoters of metabolic genes, ensuring their activation during development. Loss of PHF8 disrupts amino acid metabolism, blocks autophagy, and hinders vesicle formation.

A new study from the University of Geneva points to the brain’s waste-clearance system — the glymphatic system — as a possible piece of the psychosis puzzle. In people with 22q11.2 deletion syndrome, a high-risk genetic condition, researchers found developmental differences in an MRI-derived marker linked to glymphatic function, along with associations to hippocampal excitation/inhibition balance and psychosis vulnerability.

A team from UNIGE shows that early alterations in the brain’s clearance system could contribute to vulnerability to psychosis.

How can we explain the onset of psychotic symptoms characteristic of schizophrenia? Despite their major and often irreversible impact on intellectual abilities and autonomy, the biological mechanisms that precede their emergence remain poorly understood. A team from the Department of Psychiatry at the Faculty of Medicine and the Synapsy Center for Neuroscience Research in Mental Health at the University of Geneva (UNIGE) provides new insight into this question. Early dysfunction of the glymphatic system, the network responsible for removing waste from the brain, could be a key vulnerability factor. This research has been published in Biological Psychiatry: Global Open Science.

Hallucinations and delusions are among the characteristic psychotic symptoms of schizophrenia spectrum disorders, which may also be accompanied by social withdrawal and cognitive decline. These disorders, considered neurodevelopmental conditions, most often emerge during adolescence or early adulthood and have an estimated prevalence of 0.5–3% in the general population.