Chromosome X News and Research

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The X chromosome is one of the two sex chromosomes in humans (the other is the Y chromosome). The sex chromosomes form one of the 23 pairs of human chromosomes in each cell. The X chromosome spans about 155 million base pairs (the building blocks of DNA) and represents approximately 5 percent of the total DNA in cells.

Each person normally has one pair of sex chromosomes in each cell. Females have two X chromosomes, while males have one X and one Y chromosome. Early in embryonic development in females, one of the two X chromosomes is randomly and permanently inactivated in somatic cells (cells other than egg and sperm cells). This phenomenon is called X-inactivation or Lyonization. X-inactivation ensures that females, like males, have one functional copy of the X chromosome in each body cell. Because X-inactivation is random, in normal females the X chromosome inherited from the mother is active in some cells, and the X chromosome inherited from the father is active in other cells.

Some genes on the X chromosome escape X-inactivation. These genes are located at the tip of the short (p) arm of the X chromosome in an area known as the pseudoautosomal region. Although many genes are unique to the X or Y chromosome, genes in the pseudoautosomal region are present on both chromosomes. As a result, men and women each have two functional copies of these genes. Many genes in the pseudoautosomal region are essential for normal development.

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. The X chromosome likely contains between 900 and 1,400 genes.

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

Researchers show how DNA repairs may reshape the genome

Researchers at Duke University Medical Center and at the National Institute of Environmental Health Sciences (NIEHS) have shown how broken sections of chromosomes can recombine to change genomes and spawn new species.

13 Aug 2008

Discovery of vital key to cancer

University of Manchester scientists have uncovered the 3D structure of Mps1 - a protein that regulates the number of chromosomes during cell division and thus has an essential role in the prevention of cancer - which will lead to the design of safer and more effective therapies.

From The University of Manchester 6 Aug 2008

Scientists identify possible cause of endometriosis

Scientists at the University of Liverpool have identified an enzyme that could be responsible for a condition called endometriosis - the most common cause of pelvic pain in women.

5 Aug 2008

Anti-reflux surgery - research may lead to changes in treatment recommendations

Researchers at Wake Forest University Baptist Medical Center have found that the reflux and swallowing problems that are common symptoms in patients with Rett syndrome and other neurological impairments, may be caused by a different mechanism than they are in healthy individuals. The finding leaves researchers to wonder if these patients truly benefit from anti-reflux surgery commonly performed in these children.

4 Aug 2008

Immunotherapy shows promise in high-risk pediatric sarcomas

Based on a pilot study in children with sarcoma, researchers at the National Institutes of Health (NIH) believe that immunotherapy could prove beneficial in treating high-risk forms of this cancer.

3 Aug 2008

Inherited form of hearing loss stems from gene mutation

Pat Phalin learned she had hearing loss at 30, when she volunteered to give hearing tests at her local school. The pupils heard sounds she could not hear.

31 Jul 2008

Obesity gene makes it harder to tell if you feel full

A study involving more than 3,000 children in Britain has found those with a gene linked to obesity find it harder than others to tell when they are full.

28 Jul 2008

Suspect protein HMGB1 found to promote DNA repair, prevent cancer

An abundant chromosomal protein that binds to damaged DNA prevents cancer development by enhancing DNA repair, researchers at The University of Texas M. D. Anderson Cancer Center report online this week in the Proceedings of the National Academies of Science.

21 Jul 2008

Using genetics to improve traditional psychiatric diagnoses

Psychiatry has begun the laborious effort of preparing the DSM-V, the new iteration of its diagnostic manual. In so doing, it once again wrestles with the task set by Carl Linnaeus, to "cleave nature at its joints." However, these "joints," the boundaries between psychiatric disorders, such as that between bipolar disorder and schizophrenia, are far from clear. Prior versions of DSM followed the path outlined by Emil Kraeplin in separating these disorders into distinct categories. Yet, we now know that symptoms of bipolar disorder may be seen in patients with schizophrenia and the reverse is true, as well.

17 Jul 2008

New understanding of fetal hemoglobin regulation in patients with sickle cell disease

Although sickle cell disease is a single-gene disorder, its symptoms are highly variable. In a study published online July 14 by the Proceedings of the National Academy of Sciences, scientists at Children's Hospital Boston and the Dana Farber Cancer Institute (DFCI), in collaboration with the Broad Institute of MIT and Harvard, report five gene variants that could potentially be helpful in predicting sickle cell disease severity, perhaps even leading to better treatment approaches in the future.

15 Jul 2008

Susceptibility to pain is affected by premature birth and also genetics

Scientists in US and UK laboratories have made key discoveries into the elusive nature of pain in children and adults. The results, presented at the Forum of European Neurosciences Monday will help guide the future management and treatment of pain.

14 Jul 2008

UGA discovery could lead to new ways to attack cancers by blocking their ability to grow

Human cancer cells divide and conquer. Unless physicians can control that division with surgery, chemotherapy or radiation, the wildly dividing cells will eventually destroy a person's life.

10 Jul 2008

Scientists generate the most precise map of genetic recombination ever

Genetic recombination, the process by which sexually reproducing organisms shuffle their genetic material when producing germ cells, leads to offspring with a new genetic make-up and influences the course of evolution.

10 Jul 2008

New tool identifies genes affecting health

A new tool which makes it possible to extract information about an individual's health from genotypes in a fraction of a second, has been developed by an academic at the University of Southampton.

9 Jul 2008

Gene change sheds light on sex development disorder

One in 4,500 people suffer from a group of conditions known as sex development disorders (DSD) which occur when the sex chromosomes do not match the genitalia.

7 Jul 2008

Aventix Pharma takes over key patents for innovative screening tool for treatments for cystic fibrosis

The rights to key patents for an innovative screening tool for treatments for cystic fibrosis were transferred today to Swiss biotech company Axentis Pharma AG.

26 Jun 2008

Discovery of second genetic risk factor for developing late-onset Alzheimer's disease

Researchers have discovered the second, strong genetic risk factor for developing late-onset Alzheimer's disease, according to a new report in the June 27th issue of the journal Cell, a Cell Press publication.

25 Jun 2008

Five common genetic variations linked to metabolic syndrome and HDL cholesterol levels

Nutrition researchers at Washington University School of Medicine in St. Louis have identified five common genetic variations that increase the risk of metabolic syndrome, a group of factors linked to heart disease and diabetes. Another variant they found appeared to protect against the condition.

17 Jun 2008

Discovery of genes that regulate glucose levels

In an effort to understand how genes work, a collaborative study which includes the University of Southern California (USC) has identified a gene that regulates glucose levels. The results, which will be published in the July issue of the Journal of Clinical Investigation and is currently available online, may provide further understanding of the underlying causes of diabetes.

3 Jun 2008

Gene discovery could help answer basic questions of upright walking

What are the genes implicated in upright walking of humans? The discovery of four families in which some members only walk on all fours (quadrupedality) may help us understand how humans, unlike other primates, are able to walk for long periods on only two legs, a scientist will tell the annual conference of the European Society of Human Genetics tomorrow (Monday 2 June).

1 Jun 2008