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.

Genetic variant contributes to higher risk of lung cancer, increases tendency to smoke more

Norwegian researchers have discovered genes that increase not only one's risk of lung cancer, but perhaps one's urge to smoke as well. Now these researchers are working on developing a blood test for lung cancer.

11 Mar 2011

Research: CREBBP mutation may help cancer resist steroid treatment, fuel ALL's return

Despite dramatically improved survival rates for childhood acute lymphoblastic leukemia, relapse remains a leading cause of death from the disease. Work led by St. Jude Children's Research Hospital investigators identified mutations in a gene named CREBBP that may help the cancer resist steroid treatment and fuel ALL's return.

10 Mar 2011

New study reveals role of INK4, ARF proteins in Burkitt's lymphoma

Burkitt's lymphoma is one of the most aggressive tumors affecting humans. Multiple alterations in genes that regulate cell proliferation rate explain its aggressive behavior.

8 Mar 2011

Down’s syndrome could be detected in mother’s blood test

European researchers have devised a blood test that could help pregnant women avoid the invasive procedures now used to diagnose Down syndrome prenatally and make the diagnosis with 100% accuracy. The study report was published this Sunday in Nature Medicine.

7 Mar 2011

Novel gene therapy can promote removal of amyloid plaques and prevent Alzheimer's disease

Gene therapy that boosts the ability of brain cells to gobble up toxic proteins prevents development of Alzheimer's disease in mice that are predestined to develop it, report researchers at Georgetown University Medical Center. They say the treatment - which is given just once - could potentially do the same in people at the beginning stages of the disease.

5 Mar 2011

Research findings likely to improve understanding of gene regulation in humans

Many multi-cellular animals use sex chromosomes to determine sex. In fruit flies and in humans, this produces XX for females and XY for males. Cellular mechanisms then kick into gear to compensate the two-to-one imbalance of X-linked genes in females and males.

4 Mar 2011

Hemispherx, Chronix jointly file US patent application for CFS blood test

Chronix Biomedical announced today that it filed a provisional United States patent application jointly with Hemispherx Biopharma, Inc. on a blood test for Chronic Fatigue Syndrome.

4 Mar 2011

Novel study deepens understanding of how chromosome replication works

A novel study from the Swedish medical university Karolinska Institutet has deepened the understanding of how chromosome replication, one of life's most fundamental processes, works.

3 Mar 2011

Groundbreaking discovery in lymphoma research

BC Cancer Agency scientists have discovered that a single gene, CIITA, is implicated in almost 40 per cent of primary mediastinal B-cell lymphomas and 15 per cent of all Hodgkin lymphoma cases.

3 Mar 2011

Chromosomally unstable bowel cancer cells more resistant to chemotherapy treatments, targeted drugs

Cancer Research UK scientists have made an important step towards developing personalised bowel cancer treatment by identifying which tumours are more likely to become drug resistant, according to research published in Cancer Research today.

1 Mar 2011

Global Genes Project, 46NYC introduce t-shirts to create awareness about lack of drug treatments for rare disease

Wear That You Care. Today is Rare Disease Day and 46NYC is helping raise awareness for an important cause – this time the drug development crisis facing the rare disease patient community worldwide.

28 Feb 2011

Study: Rare genetic mutations may provide clues to improve treatment for schizophrenia

Scientists are eyeing a rare genetic glitch for clues to improved treatments for some people with schizophrenia - even though they found the mutation in only one third of 1 percent of patients.

25 Feb 2011

Foreign-born scientists and artists receive sixth annual Vilcek Prize for Biomedical Science

The Vilcek Foundation is pleased to announce the 2011 winners of its annual prizes honoring the contributions of foreign-born scientists and artists.

24 Feb 2011

Research: Gene mutation linked to schizophrenia may aid in new drug development

In a major advance for schizophrenia research, an international team of scientists led by the University of California, San Diego School of Medicine and involving Trinity College Dublin researchers has identified a gene mutation strongly linked to schizophrenia that may be an important new target for the development of drug therapies.

24 Feb 2011

NanoString launches fixed-panel assay product for human molecular karyotyping

NanoString Technologies, Inc., a privately held life sciences company marketing a complete solution for detecting and counting large sets of target molecules in biological samples, today announced the first fixed-panel assay product to be developed on its Copy Number Variation detection platform - the nCounter Human Karyotype Panel.

From NanoString Technologies 22 Feb 2011

Researchers discover new 'driver gene' in oestrogen receptor positive breast cancer

CANCER RESEARCH UK scientists have pinpointed a key cancer-causing gene that, when overactive, triggers a particularly aggressive type of breast cancer to develop.

18 Feb 2011

Metallic copper surfaces kill bacteria on contact

Metallic copper surfaces kill microbes on contact, decimating their populations, according to a paper in the February 2011 issue of the journal Applied and Environmental Microbiology. They do so literally in minutes, by causing massive membrane damage after about a minute's exposure, says the study's corresponding author, Gregor Grass of the University of Nebraska, Lincoln. This is the first study to demonstrate this mechanism of bacteriocide.

17 Feb 2011

Break-induced Replication more likely to cause genetic mutation than normal cell repair

Researchers from Indiana University-Purdue University Indianapolis and Umea- University report in a study published in the February 15, 2011, issue of PLoS Biology that a method by which cells repair breaks in their DNA, known as Break-induced Replication, is up to 2,800 times more likely to cause genetic mutation than normal cell repair.

16 Feb 2011

Researchers develop new DNA test for accurate detection of Turner syndrome in children

As a child grows, a short stature is not usually cause for concern, but it is often the only sign of a condition called Turner syndrome. Prevalent in girls, Turner syndrome is a genetic defect that short-circuits normal growth and leads to cardiac and renal problems. It is not commonly detected until age 10 or older when a youngster's unusually short height raises suspicions.