Scientists find way to create human stem cells with only 23 chromosomes, could revolutionize genetic research

BY DENIS SLATTERY, NEW YORK DAILY NEWS, Wednesday, March 16, 2016, 8:53 PM A scientific discovery unveiled Wednesday could revolutionize genetic research with new screening tools and therapies. Researchers from Columbia University Medical Center, the New York Stem Cell Foundation Research Institute and Hebrew University have found a way to create human stem cells with only 23 chromosomes, rather than the usual 46. Normally, cells with only 23 chromosomes, known as haploid cells, cannot divide on their own. Most cells in the body contain information in the form of DNA, packaged into two sets of chromosomes — one from each parent, called diploid cells. The haploid cells found in the study can be turned into any tissue in the human body, despite only containing one set of chromosomes. The discovery holds promise for therapies to treat a range of conditions, including cancer and infertility, and may even explain why humans reproduce sexually via two parents rather than one. It will allow researchers to study genetic mutations without the “interference” of the second set and help scientists discover how genes mutate and cause devastating diseases like cystic fibrosis, muscular dystrophy and Down syndrome. The study was published in the journal Nature.

Cause of Regression in Individuals with Down Syndrome Identified

Individuals with regressive Down syndrome return to baseline functioning when treated for Catatonia Judith Miles found that Catatonia, a treatable disorder, may cause regression in patients with Down syndrome. May 12, 2015 By: Fran Webber COLUMBIA, Mo. – Down syndrome, the most common chromosomal disorder in America, can be complicated by significant deterioration in movement, speech and functioning in some adolescents and young adults. Physicians previously attributed this regression to depression or early-onset Alzheimer’s, and it has not responded to treatments. Now, a researcher at the University of Missouri has found that Catatonia, a treatable disorder, may cause regression in patients with Down syndrome. Individuals with regressive Down syndrome who were treated for Catatonia showed improvement, the researcher found. “Our findings are important for young people with Down syndrome, autism and probably other neurodevelopmental disorders,” said Judith Miles, professor emerita in the MU School of Medicine and researcher with the MU Thompson Center for Autism and Neurodevelopmental Disorders. “Until recently, Catatonia was felt to be just a complication of schizophrenia; however, it now is known that Catatonia is a common neuropsychiatric disorder that complicates many types of brain disorders. Our recognition that Catatonia occurs in young adults and adolescents with Down syndrome means these individuals who before were relegated to lives of incapacity may now receive treatments that restore them to their usual levels of activity.” Those who care for individuals with regressive Down syndrome describe them as “zombie-like,” Miles said. Symptoms of regression can include difficulty moving and sleeping, inability to perform activities of daily living, no longer talking, and a lack of interest in previously enjoyed activities. In her study, Miles followed the cases of four patients with Down syndrome who were diagnosed with [...]

Down syndrome gene-silencing strategy

Medical News Today, by Staff ~ October 24, 2013 The first evidence that the underlying genetic defect responsible for trisomy 21, also known as Down syndrome, can be suppressed in laboratory cultures of patient-derived stem cells was presented at the American Society of Human Genetics 2013 annual meeting in Boston. People with Down syndrome are born with an extra chromosome 21, which results in a variety of physical and cognitive ill effects. In laboratory cultures of cells from patients with Down syndrome, an advanced genome editing tool was successfully used to silence the genes on the extra chromosome, thereby neutralizing it, said Jeanne Lawrence, Ph.D., Professor of Cell & Developmental Biology at the University Massachusetts Medical School, Worcester, MA. Dr. Lawrence and her team compared trisomic stem cells derived from patients with Down syndrome in which the extra chromosome 21 was silenced to identical cells from patients that were untreated. The researchers identified defects in the proliferation, or rapid growth, of the untreated cells and the differentiation, or specialization, of untreated nervous system cells. These defects were reversed in trisomic stem cells in which the extra chromosome 21 was muted. "Silencing of trisomy 21 by manipulation of a single gene in living cells in laboratory cells surmounts the first major obstacle to development of potential 'chromosome therapy,'" said Dr. Lawrence, whose presentation today provided an update to the results that she and her colleagues reported earlier this year in the journal Nature (Jiang et al. 2013) In her ASHG presentation, Dr. Lawrence described the use of the novel editing tool to examine changes in gene expression that result from the silencing of the extra chromosome. The changes in gene expression were not limited to chromosome [...]

Mouse Study Offers Hope For Potential Down Syndrome Treatment

Red Orbit, by April Flowers ~ September 5, 2013 A new compound that dramatically bolsters learning and memory when given on the day of birth to mice with a Down syndrome-like condition has been identified by researchers from Johns Hopkins and the National Institutes of Health (NIH). The findings, published in Science Translational Medicine, shows that the single-dose treatment seems to enable the cerebellum of the rodent’s brains to grow to a normal size. The compound is a small molecule known as a sonic hedgehog pathway agonist. The research team cautions that it has not been proven safe for human trials in people with Down syndrome. However, they believe their experiments do hold promise for developing drugs like it. “Most people with Down syndrome have a cerebellum that’s about 60 percent of the normal size,” says Roger Harper Reeves, PhD, a professor in the McKusick-Nathans Institute of Genetic Medicine at the Johns Hopkins University School of Medicine. “We treated the Down syndrome-like mice with a compound we thought might normalize the cerebellum’s growth, and it worked beautifully. What we didn’t expect were the effects on learning and memory, which are generally controlled by the hippocampus, not the cerebellum.” Down syndrome, a condition that occurs when people have three, rather than the usual two, copies of chromosome 21, has been the focus of Reeves’ career. Because of this “trisomy,” extra copies of more than 300 genes housed on that chromosome are present in people with Down syndrome. These extra genes lead to intellectual disabilities, distinctive facial features and sometimes heart problems and other health effects. Developing treatments is complicated and difficult since the condition involves so many genes. The current study used mice that were genetically [...]