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Archive - Feb 27, 2020

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Researchers Discover Second Type of Schizophrenia; In a Study of More Than 300 Patients from Three Continents, Over One Third Had Brains That Looked Similar to Those in Healthy People

Penn Medicine researchers are the first to discover two distinct neuroanatomical subtypes of schizophrenia after analyzing the brain scans of over 300 patients. The first type showed lower widespread volumes of gray matter when compare to healthy controls, while the second type had volumes largely similar to those in normal brains. The findings, published online on February 27, 2020 in Brain, suggest that, in the future, accounting for these differences could inform more personalized treatment options. "Numerous other studies have shown that people with schizophrenia have significantly smaller volumes of brain tissue than healthy controls. However, for at least a third of patients we looked at, this was not the case at all -- their brains were almost completely normal," said principal investigator Christos Davatzikos, PhD, the Wallace T. Miller Professor of Radiology in the Perelman School of Medicine at the University of Pennsylvania. "In the future, we're not going to be saying, 'This patient has schizophrenia,' We're going to be saying, 'This patient has this subtype' or 'this abnormal pattern,' rather than having a wide umbrella under which everyone is categorized." Schizophrenia is a poorly understood mental disorder that typically presents with hallucinations, delusions, and other cognitive issues -- though symptoms and responses to treatment vary widely from patient to patient. Up until now, attempts to study the disease, by comparing healthy to diseased brains, has neglected to account for this heterogeneity, which Dr. Davatzikos says has muddled research findings and undermined clinical care. To better characterize the distinct brain differences within the schizophrenia patient population, Dr.

Huntington's Disease-Causing DNA Repeat Mutations Reversed in the Lab; International Team Identifies Compound That Could Slow Huntington's Disease Onset and Progression In Humans

Neurodegenerative diseases, like Huntington's disease and myotonic dystrophy, are often referred to as DNA repeat diseases, named because of long repeated sequences in the DNA of patients. Increasing repeat expansion length in the affected tissues contribute to earlier age of disease onset and worsen the progression and severity of the disease over time. In an international study published online on February 14, 2020 Nature Genetics, scientists from The Hospital for Sick Children (SickKids), Canada, along with research teams from Osaka University, Japan, reveal the ability to reverse this repeat mutation length in the brains of a mouse model with Huntington's disease. The article is titled “"A Slipped-CAG DNA-Binding Small Molecule Induces Trinucleotide-Repeat Contractions in Vivo.” The team discovered a compound that targets the unusual DNA structure and was shown to reverse repeat expansions with undetectable off-target effects. Huntington's disease is one of more than 40 neurodegenerative diseases caused by DNA repeat expansion mutations in specific genes. The unusual DNA structures, called slipped-DNAs, are formed by the repeats, and levels of slipped-DNAs are greater in affected tissues that have longer repeat expansions, causing more severe mutations. The study found evidence that the molecule compound called naphthyridine-azaquinolone (NA) can recognize slipped-DNAs and reverse the mutation -- essentially causing a contraction of the expansion. In the lab, the research team was able to successfully reduce the repeat expansions in the brain of a Huntington's disease mouse model, as well as in cells extracted from tissues of individuals affected by Huntington's disease.