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.
People with Alzheimer’s and Down syndrome may benefit from participating in Alzheimer’s clinical trials

People with Alzheimer’s and Down syndrome may benefit from participating in Alzheimer’s clinical trials

Study reveals why viral infections are less frequent but more severe in individuals with Down syndrome

Study reveals why viral infections are less frequent but more severe in individuals with Down syndrome

GnRH therapy could improve cognitive deficits in men with Down syndrome

GnRH therapy could improve cognitive deficits in men with Down syndrome

Study addresses food texture challenges in the life of children with Down syndrome

Study addresses food texture challenges in the life of children with Down syndrome

Simple blood test can accurately detect Alzheimer's disease in people with Down syndrome

Simple blood test can accurately detect Alzheimer's disease in people with Down syndrome

"Selfish chromosomes" explain why most human embryos die very early on, study suggests

"Selfish chromosomes" explain why most human embryos die very early on, study suggests

Antiretroviral drug used to treat HIV ameliorates cognitive deficits in mouse model of Down syndrome

Antiretroviral drug used to treat HIV ameliorates cognitive deficits in mouse model of Down syndrome

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

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

Optical genome mapping could change the existing workflow within cytogenetic laboratories

Optical genome mapping could change the existing workflow within cytogenetic laboratories

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

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

Study shows potential benefits of green tea extracts in Down syndrome

Study shows potential benefits of green tea extracts in Down syndrome

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

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

COVID-19 severity could be linked to genetic variance

COVID-19 severity could be linked to genetic variance

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

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

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

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

Life-threatening COVID-19 associated with specific genetic variants

Life-threatening COVID-19 associated with specific genetic variants

New therapeutic possibilities for treating intellectual disability in Down syndrome

New therapeutic possibilities for treating intellectual disability in Down syndrome

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

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

MU researchers describe Down syndrome-associated catatonia

MU researchers describe Down syndrome-associated catatonia

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

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