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.

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

European scientists aim to identify causes of dementia

Dementia is common to a variety of neurodegenerative diseases such as Alzheimer's disease, Parkinson disease and Down syndrome. This common symptom is one of the major causes of disability and dependency among older people.

19 Dec 2018

MUHC's 'Dr. House' discovers new genetic disease and the gene responsible for it

A team from the Research Institute of the McGill University Health Centre led by Dr. Donald Vinh, the RI's so-called "Dr. House" because of his research into rare diseases, has discovered a new human disease and the gene responsible for it, paving the way for the proper diagnosis of patients globally and the development of new therapies.

7 Dec 2018

Down syndrome may hold important clues to onset of Alzheimer's disease

At first glance, Down syndrome and Alzheimer's disease, two severe brain abnormalities, may seem to have little in common. Down syndrome is a hereditary disease, the source of which has long been recognized--a triplication of chromosome 21.

17 Oct 2018

Children born with Down's syndrome have superior genome that compensates for disability

Down's syndrome - also known as trisomy 21 - is a genetic disorder caused by an additional third chromosome 21. Although this genetic abnormality is found in one out of 700 births, only 20% of foetuses with trisomy 21 reach full term.

19 Jan 2018

New technique may reveal clues about role of centromeres in Down syndrome, other birth defects

Some scientists call it the "final frontier" of our DNA -- even though it lies at the center of every X-shaped chromosome in nearly every one of our cells.

20 Nov 2017

Research aims to raise awareness of higher rate of testicular cancer in patients with DS

Research by Jue Wang, MD, at the University of Arizona Cancer Center at Dignity Health St. Joseph's Hospital and Medical Center on "Delay in Diagnosis of Testicular Cancer in a Patient with Down Syndrome" was published in the October issue of Journal of Cancer and Therapeutic Science.

13 Oct 2017

MIT biologists identify how the immune system eliminates genetically imbalanced cells

Most living cells have a defined number of chromosomes: Human cells, for example, have 23 pairs. As cells divide, they can make errors that lead to a gain or loss of chromosomes, which is usually very harmful.

20 Jun 2017

Phase 2 clinical study examines Alzheimer's disease drug to treat adults with Down syndrome

A phase 2 clinical trial in young adults with Down syndrome of a drug being investigated for the treatment of Alzheimer's disease supports further investigation of its potential.

1 Jun 2017

Research findings may provide answers for infertility in older women

Findings from new research led by the Monash Biomedicine Discovery Institute and University College London may finally resolve, and potentially provide answers, as to why older women have higher incidences of miscarriage and have babies with chromosomal abnormalities.

18 May 2017