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.

MBL scientists develop novel methods to interpret cellular dynamics

If you can imagine identical twin sisters at rest, their breath drawing them subtly together and apart, who somehow latch onto ropes that pull them to opposite sides of the bed-you can imagine what happens to a chromosome in the dividing cell.

11 Mar 2010

Genetic basis unknown in many children with mental retardation and developmental delays

Researchers from four laboratories that perform diagnostic genetic testing of chromosome abnormalities in individuals with unexplained physical and developmental disabilities recently identified a previously unrecognized genetic disorder.

10 Mar 2010

Genetic variant increases risk of lung cancer for light and heavy smokers, say researchers

Individuals with a certain type of genetic susceptibility to lung cancer face a greatly increased risk for the deadly disease with even a small exposure to cigarette smoke, a study team that includes researchers from the University of Cincinnati has concluded.

10 Mar 2010

USF study: HHV-6 causes permanent infection by inserting its DNA into human chromosomes

Human herpesvirus 6 (HHV-6) infects nearly 100 percent of humans in early childhood, and the infection then lasts for the rest of a person's life. Now, a team led by Peter Medveczky, MD, a professor in the Department of Molecular Medicine at the University of South Florida, has discovered that in some individuals, HHV-6 causes such a permanent infection by inserting or "integrating" its DNA into human chromosomes.

9 Mar 2010

ITCH gene causes multisystem autoimmune disorder

The gene for a newly recognized disease has been identified thanks to the determination of an Amish father and the clinical skills and persistence of Indiana University and Riley Hospital for Children physicians in collaboration with physicians and researchers at the Clinic for Special Children in Lancaster County, Penn., which specializes in disorders of the Amish.

9 Mar 2010

RDS launches international outreach program on cognitive impairment in Down syndrome patients

Research Down Syndrome has launched an international outreach program to focus awareness and support for the rapidly advancing area of biomedical research leading to safe and effective approved medical therapies to treat cognitive impairment in individuals of all ages with Down syndrome -- improving memory, learning and communication.

9 Mar 2010

Scientists identify EoE-associated region in human chromosome

Scientists have identified a region of a human chromosome that is associated with eosinophilic esophagitis (EoE), a recently recognized allergic disease. People with EoE frequently have difficulty eating or may be allergic to one or more foods. This study further suggests that a suspected so-called master allergy gene may play a role in the development of this rare but debilitating disorder.

8 Mar 2010

Pediatrics researchers identify major gene location responsible for EoE

Pediatrics researchers have identified the first major gene location responsible for a severe, often painful type of food allergy called eosinophilic esophagitis (EoE). In this disease, which may cause weight loss, vomiting, heartburn and swallowing difficulties, a patient may be unable to eat a wide variety of foods.

7 Mar 2010

ARIAD Pharmaceuticals' investigational pan-BCR-ABL inhibitor receives FDA and EMA orphan drug designation

ARIAD Pharmaceuticals, Inc. today announced that its investigational pan-BCR-ABL inhibitor, AP24534, has been granted orphan drug designation by both the U. S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA). In the U.S., the orphan designation of AP24534 is for the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) and in the E.U., its orphan designation is for CML and acute lymphoblastic leukemia.

2 Mar 2010

Determining personal risk for genetic disorders essential

Genetic diseases affect an estimated 12 million Americans, yet according to a survey of 1,000 people conducted by the Genetic Disease Foundation (GDF), while two-thirds of those surveyed were willing to and saw the benefits of undergoing genetic testing, close to 80 percent had never talked to their physician about genetic screening – an inconsistency that can have serious implications on a person's overall health and the health of their immediate family members.

1 Mar 2010

Researchers find gene regulator that plays key role in DS-AMKL

Between 5 and 10 percent of babies with Down syndrome develop a transient form of leukemia that usually resolves on its own. However, for reasons that haven't been clear, 20 to 30 percent of these babies progress to a more serious leukemia known as Down syndrome acute megakaryoblastic leukemia (DS-AMKL), which affects the blood progenitor cells that form red blood cells and platelets.

1 Mar 2010

For people who carry common gene variants, smoking increases risk of aneurysm

For people who carry common gene variants, cigarette smoking greatly increases the risk that a blood vessel in the brain will weaken and balloon out - called an aneurysm - which could be life-threatening if it ruptures, according to research presented at the American Stroke Association's International Stroke Conference 2010.

27 Feb 2010

MLL cancer cells rely on normal protein to proliferate

Researchers have found that one particularly aggressive type of blood cancer, mixed lineage leukemia (MLL), has an unusual way to keep the molecular motors running. The cancer cells rely on the normal version of an associated protein to stay alive.

27 Feb 2010

Ferring Pharmaceuticals, GSN sign agreement to test Parental Support technology

Ferring Pharmaceuticals and Gene Security Network announced that they have signed an agreement to conduct a clinical trial of GSN's advanced preimplantation genetic diagnosis (PGD) technology, Parental Support™.

26 Feb 2010

QR Pharma awarded patent covering use of Posiphen and analogs in treatment of DS

QR Pharma, Inc., a developer of novel drugs to treat Alzheimer’s disease (AD), announced today that it was issued U.S. Patent No. 7,625,942, a "Method of Treating Down Syndrome" by the U.S. Patent and Trademark Office. The '942 patent covers use of Posiphen and analogs to treat cognitive impairments associated with Down Syndrome (DS). This patent valuably expands upon the original Posiphen and analog patent that claims composition of matter and use of compounds to lower amyloid-β precursor protein (APP) and thereby treat dementia and Alzheimer’s disease (AD).

24 Feb 2010

ES cells-functions: Condensins promote mitotic progression and maintain interphase chromatin compaction

Regulatory proteins common to all eukaryotic cells can have additional, unique functions in embryonic stem (ES) cells, according to a study in the February 22 issue of the Journal of Cell Biology (www.jcb.org). If cancer progenitor cells-which function similarly to stem cells-are shown to rely on these regulatory proteins in the same way, it may be possible to target them therapeutically without harming healthy neighboring cells.

24 Feb 2010

New genetic data may help predict risk for end-stage kidney disease

Israeli and American researchers have identified new genetic data that could be used in the future to predict who will develop end-stage kidney disease (ESKD). ESKD requires dialysis or transplantation to sustain life, and is fatal in most regions of the world, where these treatments are not available.

24 Feb 2010

DNA interval in unexplored region of human genome increases risk for coronary artery disease

Scientists from the U.S. Department of Energy's Lawrence Berkeley National Laboratory have learned how an interval of DNA in an unexplored region of the human genome increases the risk for coronary artery disease, the leading cause of death worldwide.

23 Feb 2010

Researchers use new technology to reveal different genetic patterns of neuroblastoma

Researchers at the Sahlgrenska Academy at the University of Gothenburg, Sweden and Karolinska Institutet have used novel technology to reveal the different genetic patterns of neuroblastoma, an aggressive form of childhood cancer. This discovery may lead to significant advances in the treatment of this malignant disease, which mainly affects small children.

22 Feb 2010

New gene locus influencing risk for atrial fibrillation identified

Atrial fibrillation is a cardiac arrhythmia - a chronic irregularity of heartbeat - which affects an estimated 1 million people in Germany. Although the condition is not acutely life-threatening, it does increase the risk of developing more serious illnesses, such as cardiac insufficiency, stroke and dementia. In the third of a series of genomewide asssociation studies, an international team of researchers, led by LMU physician PD Dr. Stefan K--b, now reports the identification of a new gene locus that has a significant influence on risk for atrial fibrillation.

22 Feb 2010

Chromosome X News and Research

Further Reading

MBL scientists develop novel methods to interpret cellular dynamics

Genetic basis unknown in many children with mental retardation and developmental delays

Genetic variant increases risk of lung cancer for light and heavy smokers, say researchers

USF study: HHV-6 causes permanent infection by inserting its DNA into human chromosomes

ITCH gene causes multisystem autoimmune disorder

RDS launches international outreach program on cognitive impairment in Down syndrome patients

Scientists identify EoE-associated region in human chromosome

Pediatrics researchers identify major gene location responsible for EoE

ARIAD Pharmaceuticals' investigational pan-BCR-ABL inhibitor receives FDA and EMA orphan drug designation

Determining personal risk for genetic disorders essential

Researchers find gene regulator that plays key role in DS-AMKL

For people who carry common gene variants, smoking increases risk of aneurysm

MLL cancer cells rely on normal protein to proliferate

Ferring Pharmaceuticals, GSN sign agreement to test Parental Support technology

QR Pharma awarded patent covering use of Posiphen and analogs in treatment of DS

ES cells-functions: Condensins promote mitotic progression and maintain interphase chromatin compaction

New genetic data may help predict risk for end-stage kidney disease

DNA interval in unexplored region of human genome increases risk for coronary artery disease

Researchers use new technology to reveal different genetic patterns of neuroblastoma

New gene locus influencing risk for atrial fibrillation identified

Achieving and maintaining ISO/IEC 27001 and BS 10012 certifications

Expanding research and clinical options for children with cancer

Examining how pain could play a direct protective role in the gut

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