Chromosome 21 News and Research

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Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 21, one copy inherited from each parent, form one of the pairs. Chromosome 21 is the smallest human chromosome, spanning about 47 million base pairs (the building blocks of DNA) and representing approximately 1.5 percent of the total DNA in cells.

In 2000, researchers working on the Human Genome Project announced that they had determined the sequence of base pairs that make up this chromosome. Chromosome 21 was the second human chromosome to be fully sequenced.

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 21 likely contains between 300 and 400 genes.

Genes on chromosome 21 are among the estimated 20,000 to 25,000 total genes in the human genome.

Study explores connections between COVID-19 severity and gene expression in immune cells

New research shows how genetic variations linked to severe cases of COVID-19 affect our immune cells.

21 Nov 2021

Optical genome mapping could change the existing workflow within cytogenetic laboratories

Dutch-French research shows that Optical Genome Mapping (OGM) detects abnormalities in chromosomes and DNA very quickly, effectively and accurately. Sometimes even better than all existing techniques together, as they describe in two proof-of-concept studies published in the American Journal of Human Genetics.

8 Jul 2021

High-powered MRI detects subtle differences in the hippocampus of people with Down syndrome

Using ultra-high field magnetic resonance imaging (MRI) to map the brains of people with Down syndrome (DS), researchers from Case Western Reserve University, Cleveland Clinic, University Hospitals and other institutions detected subtle differences in the structure and function of the hippocampus--a region of the brain tied to memory and learning.

29 Apr 2021

Study shows potential benefits of green tea extracts in Down syndrome

A new study led by Belgian and Spanish researchers published in Scientific Reports adds evidence about the potential benefits of green tea extracts in Down syndrome.

3 Mar 2021

Adults with Down syndrome more likely to die from COVID-19 than general population

A new study by an international team of researchers found that adults with Down syndrome are more likely to die from COVID-19 than the general population, supporting the need to prioritize vaccinating people with the genetic disorder.

22 Feb 2021

COVID-19 severity could be linked to genetic variance

A new study describes some potentially important genetic factors in the host that may shape the clinical symptoms and signs of the disease.

23 Dec 2020

Research can bring new possibilities for earlier diagnosis, preventive treatment of dementia

Researchers at Karolinska Institutet in Sweden have studied the incidence and regional distribution of Alzheimer's disease biomarkers in the brains of people with Down's syndrome.

23 Nov 2020

$109 million NIH grant awarded to expand Alzheimer's disease and Down syndrome research

The Alzheimer's Biomarkers Consortium - Down Syndrome, a multi-institution research team, co-led by members from the University of California, Irvine, has been awarded an unprecedented five-year, $109 million grant by the National Institutes of Health, to expand research on the biomarkers of Alzheimer's disease in adults with Down syndrome.

22 Oct 2020

Life-threatening COVID-19 associated with specific genetic variants

Results of a genome-wide association study on 2,244 critically-ill patients due to coronavirus disease (COVID-19) from 208 intensive care units across the United Kingdom revealed significant host-specific genetic determinants that can predispose people to the severe form of the disease. The report is currently available on the medRxiv preprint server.

28 Sep 2020

New therapeutic possibilities for treating intellectual disability in Down syndrome

A team of researchers has studied the neural basis of intellectual disability in mice with Down syndrome and has discovered that the neural networks of brain circuits relevant to memory and learning are over-activated and that the connectivity of these circuits is poor.

5 May 2020

Modifiable risk factors could play important role in Alzheimer's disease, study finds

Amyloid is a key feature of Alzheimer's disease, but the accumulation of these sticky proteins may not be the only risk factor for developing Alzheimer's disease, according to a new study published this week.

8 Apr 2020

MU researchers describe Down syndrome-associated catatonia

Down syndrome, due to an extra chromosome 21, occurs in 250,000 children and adults in the United States, making it the country's most common chromosomal disorder. Inherited heart defects, thyroid cancer, celiac disease and developmental disabilities are common Down syndrome complications.

19 Nov 2019

Scientists reverse learning and memory deficits with drugs in animal model of Down syndrome

In a surprising finding using the standard animal model of Down syndrome (DS), scientists were able to correct the learning and memory deficits associated with the condition -- the leading genetic cause of cognitive disability and the most frequently diagnosed chromosomal disorder in the U.S. -- with drugs that target the body's response to cellular stresses.

15 Nov 2019

Study uncovers cause for spatial-memory deficits in people with Down syndrome

Professor Juan Lerma's group, from the UMH-CSIC Institute of Neurosciences, in Alicante, has identified the gene called GRIK1, fundamental in the balance between excitation and inhibition in the brain, as one of the causes for people with Down syndrome having spatial orientation problems.

1 Nov 2019

Wisconsin study: 3 in 5 people with Down syndrome diagnosed with dementia by age 55

Not so many years ago, people with Down syndrome rarely survived to middle age. Many died young due to heart problems associated with the congenital condition.

29 Oct 2019

Researchers receive $3.2 million NIH grant to pursue a deeper understanding of Down syndrome

Mount Sinai researchers have been awarded a $3.2 million grant from the National Institutes of Health to pursue a deeper understanding of Down syndrome, the most common genetic cause of intellectual and developmental disabilities in children and young adults, affecting more than 200,000 individuals in the United States.

22 Oct 2019

BU professor awarded NIH grant to study Down syndrome

Tarik F. Haydar, PhD, professor of anatomy and neurobiology at Boston University School of Medicine, has been awarded a two-year Exploratory/Developmental Research Grant Award (R21) from the National Institutes of Health.

16 Jul 2019

Rutgers-led study pinpoints key gene linked to impaired memory in Down syndrome

Targeting a key gene before birth could someday help lead to a treatment for Down syndrome by reversing abnormal embryonic brain development and improving cognitive function after birth, according to a Rutgers-led study.

24 May 2019

MIT announces creation of the Alana Down Syndrome Center

As part of MIT's continued mission to help build a better world, the Institute announced the creation of the Alana Down Syndrome Center, an innovative new research endeavor, technology development initiative, and fellowship program launched with a $28.6 million gift from Alana Foundation, a nonprofit organization started by Ana Lucia Villela of São Paulo, Brazil.

21 Mar 2019

Cannabinoid receptor type 1 appears to be potential target to treat Down syndrome

A study by the Neuropharmacology Laboratory-NeuroPhar of the Department of Experimental and Health Sciences at UPF reveals the involvement of the endocannabinoid system in cognitive disorders in mouse models of Down syndrome.

7 Feb 2019