The development of an embryo in its early stages involves a series of processes in which cells interact and organize to form tissues. In humans, these stages are studied with animal models, stem cells and cell aggregates that mimic natural development phases, or with human embryos, depending on their availability and a strict protocol. Now, in back-to-back papers published online in Nature, scientists from Yale University and the University of Cambridge have two new embryonic models formed from human stem cells to study development after embryo implantation in the uterus.

Back-to-back papers in the June 22, 2023, issue of Nature have identified separate molecular mechanisms underlying sex-specific cancer outcomes. Researchers from The University of Texas MD Anderson Cancer Center showed that increased expression of the epigenetic enzyme KDM5D, which is located on the Y chromosome, contributed to cancer progression in KRAS-mutated tumors. In the same issue of Nature, a team from Cedars-Sinai reported new insights into the consequences of losing the entire Y chromosome.

Barring truly major surprises, exagamglogene autotemcel (Exa-cel, Vertex Pharmaceuticals Inc.) is on track to become the first approved CRISPR-based gene editing therapy. It is partly in expectation of Exa-cel’s approval that the European Hematology Association (EHA) and the European Society for Bone Marrow Transplantation hosted a session on “transplantation versus gene therapy in sickle cell disease.”

The discovery of DNA was a milestone in the history of science that led to a breakthrough in biomedical research. By associating disease and genetics, genome correction techniques were ultimately developed that are supposed to work in the same way that antibiotics and antivirals block pathogenic microorganisms: by directly attacking the causes of disease.

The most ambitious objective of any treatment is to eradicate the disease, acting on its origin to cure it instead of treating its symptoms. This is the purpose of the gene therapy against type 2 diabetes (T2D) and obesity that Fractyl Health Inc. is developing. Scientists from the Lexington, Mass.-based company have designed a strategy based on glucagon-like peptide-1 (GLP-1) to transform pancreatic cells and reverse the disease.

Investigators have identified a second individual who remained cognitively normal into his late 60s despite having the PSEN1 E280A mutation, which causes a familial version of early-onset Alzheimer’s disease (AD). The likely source of protection, a mutation in a gene called Reelin, is distinct from the protective mechanism identified in the first case of an individual who was protected from the effects of PSEN1 E280A. That case was reported in 2019.

The human genome, the sequence that represents the DNA of our species, was built with a single individual as a model. This all-in-one standard didn’t include the gene variations that make us different or explain why some people develop certain diseases. Four simultaneous studies from the Human Pangenome Reference Consortium have published a sequence based on 47 individuals, beginning to capture the genetic diversity that defines humans.

By analyzing a cohort of adolescents that developed myocarditis or pericarditis after vaccination against SARS-CoV-2 vaccination, researchers from Yale University School of Medicine were able to pinpoint the underlying mechanism as an overly active innate immune response to the vaccine that led to broad activation of T cells and natural killer (NK) cells. Myocarditis “has been seen in other vaccine contexts, though is most common after viral infection,” Carrie Lucas told reporters at a press conference announcing the findings.

A base-by-base comparison of the genome sequences of 240 species of mammals has pinpointed sites in the human genome where mutations are likely to cause disease. The sites are all perfectly conserved across the mammalian family tree over 100 million years of evolution, indicating they underlie fundamental biological processes that do not tolerate diversity or change very well.

Synonymous or silent mutations do not change the sequence of the protein that they encode. With some exceptions, they do not trigger any effect. Last year, however, a study by researchers from the University of Michigan tried to refute this concept after finding that they altered the protein function. But breaking dogmas can have answers. A group of scientists from various institutions has found that this work could have a method error.