Chromosome X News and Research

RSS

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.

Blood test and gene sequencing combined to detect cancer

Scientists at the Johns Hopkins Kimmel Cancer Center have combined the ability to detect cancer DNA in the blood with genome sequencing technology in a test that could be used to screen for cancers, monitor cancer patients for recurrence and find residual cancer left after surgery.

29 Nov 2012

Study broadens understanding of how cells regulate X chromosome inactivation

In a paper published in the Nov. 21 issue of Cell, a team led by Mauro Calabrese, a postdoctoral fellow at the University of North Carolina in the lab of Terry Magnuson, chair of the department of genetics and member of the UNC Lineberger Comprehensive Cancer Center, broadens the understanding of how cells regulate silencing of the X chromosome in a process known as X-inactivation.

28 Nov 2012

Gadd45g protein essential in initiating development of male sex organs

Scientists at the Institute of Molecular Biology (IMB) in Mainz have identified a protein essential for initiating the development of male sex organs. Loss of the gene Gadd45g results in complete sex reversal of male mice, making them appear female.

28 Nov 2012

Glycoprotein gene flags up heart disease

The glycosylphosphotidylinositol-anchored membrane glycoprotein CD14 gene significantly predicts cardiovascular mortality in adults aged 65 years or over, research shows.

20 Nov 2012

IL-13 receptor system could play a major role in Parkinson's

Deciphering what causes the brain cell degeneration of Parkinson's disease has remained a perplexing challenge for scientists. But a team led by scientists from The Scripps Research Institute (TSRI) has pinpointed a key factor controlling damage to brain cells in a mouse model of Parkinson's disease.

20 Nov 2012

Researchers discover new gene for susceptibility to Alzheimer's disease

A large-scale international study involving French researchers from the Inserm-Institut Pasteur Lille-Universit- Lille Nord de France "Public health and molecular epidemiology of ageing-related diseases" joint research unit led by Philippe Amouyel, has just discovered a gene for susceptibility to a rare disease that causes susceptibility to a common one, Alzheimer's disease, providing evidence of the heterogeneous aetiology of Alzheimer's disease.

20 Nov 2012

AGTR2 gene variant predicts risk for preeclampsia

Carriers of a variant of the angiotensin II receptor, type 2 gene have increased risk for preeclampsia during pregnancy if they are also overweight or obese, show study results published in Placenta.

19 Nov 2012

Genetic link between rheumatoid arthritis and the X chromosome

Researchers have pieced together new genetic clues to the arthritis puzzle in a study that brings potential treatments closer to reality and could also provide insights into why more women than men succumb to the disabling condition.

15 Nov 2012

Researchers describe structure of active site core of topoisomerase II alpha anti-cancer drug target

A group of researchers at the University of California, Berkeley have for the first time described the structure of the active site core of topoisomerase II alpha, an important target for anti-cancer drugs.

15 Nov 2012

Study on genetic capacity of diverse populations to make critical PUFAs

World-renowned scientists are taking what they've learned from their multicenter research collaboration studying the health impact of fatty acids on diverse populations to set up a genetics center in India.

8 Nov 2012

Studies provide first clues of balanced de novo chromosomal rearrangements

Whole genome sequencing of the DNA code of three prenatal samples provided a detailed map of the locations of their chromosomal abnormalities in 14 days, scientists reported today at the American Society of Human Genetics (ASHG) 2012 meeting in San Francisco.

8 Nov 2012

Chromosome 22q11.2 deletion syndrome anxiety linked to poorer adaptive behaviors

UC Davis researchers have found that for children with the genetic disorder known as chromosome 22q11.2 deletion syndrome anxiety -- but not intelligence -- is linked to poorer adaptive behaviors, such as self-care and communication skills, that affect daily life. The developmental syndrome, which is associated with a constellation of physical, cognitive and psychiatric problems, usually is apparent at birth or early childhood, and leads to lifelong challenges.

6 Nov 2012

Dysregulation of CISTR-ACT causes brachydactyly type E

The patients have single short fingers (metacarpals) and toes (metatarsals) and can be restricted in growth due to a shortened skeleton. This hereditary disease is called brachydactyly type E (Greek for short fingers).

6 Nov 2012

Pfizer receives FDA approval for Synribo to treat chronic myelogenous leukemia

The U.S. Food and Drug Administration today approved Synribo (omacetaxine mepesuccinate) to treat adults with chronic myelogenous leukemia (CML), a blood and bone marrow disease.

29 Oct 2012

FDA accepts ARIAD’s ponatinib NDA for filing

ARIAD Pharmaceuticals, Inc. today announced that the U.S. Food and Drug Administration (FDA) has accepted for filing the New Drug Application (NDA) for accelerated review of ARIAD's investigational BCR-ABL inhibitor, ponatinib, in patients with resistant or intolerant chronic myeloid leukemia (CML) or Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL).

25 Oct 2012

Two papers connect lncRNAs to inherited conditions in humans

LncRNAs are long non-coding RNAs that are emerging as important regulators of gene expression in biological processes and diseases. In this issue of the Journal of Clinical Investigation, two papers connect lncRNAs to inherited conditions in humans.

25 Oct 2012

Paper details new target for anti-cancer drug development

In a new paper released today in Nature, BioFrontiers Institute scientists at the University of Colorado Boulder, Tom Cech and Leslie Leinwand, detailed a new target for anti-cancer drug development that is sitting at the ends of our DNA.

25 Oct 2012

Lipid droplets play an unexpected role in embryo development

Histones are proteins needed to assemble DNA molecules into chromosomes. They have long represented a classic balancing act in biology; too few histone molecules result in DNA damage, while too many histones are toxic to the cell. New research at the University of Rochester is causing a fundamental shift in the concept of histone balance and the mechanism behind it.

19 Oct 2012

METASTROKE refines genetic stroke culprits

An analysis from the METASTROKE collaboration confirms an increased stroke risk associated with four previously reported genetic loci and shows that these are specific to certain stroke subtypes.

15 Oct 2012

Chromosome 3p21.1 locus contains common genetic risk for bipolar disorder

One of the biggest challenges in psychiatric genetics has been to replicate findings across large studies. Scientists at King's College London, Institute of Psychiatry have now performed one of the largest ever genetic replication studies of bipolar affective disorder, with 28,000 subjects recruited from 36 different research centers. Their findings provide compelling evidence that the chromosome 3p21.1 locus contains a common genetic risk for bipolar disorder, the PBRM1 gene.

15 Oct 2012