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 identify cause of rare syndrome consistent with Fanconi Anemia

An international team of researchers has established the cause of rare syndrome consistent with Fanconi Anemia: a de novo mutation in a so called RAD51 gene, which is responsible for repairing damages in the DNA.

23 Dec 2015

Mitochondrial variation and viable pregnancy: an interview with Dr Elpida Fragouli

Embryos require adequate amounts of energy so that they can successfully progress through each of their cell divisions.

16 Dec 2015

Report uncovers how Down syndrome hampers nervous system that plays key role in health, longevity

While most Down syndrome research has focused on the brain, a new report by Johns Hopkins University biologists uncovers how the disorder hampers a separate part of the nervous system that plays a key role in health and longevity.

14 Dec 2015

Whitehead researchers create 3D map to predict how genes are regulated in normal cells

Whitehead Institute researchers have created a map of the DNA loops that comprise the three dimensional (3D) structure of the human genome and regulate gene expression in human embryonic stem (ES) cells and adult cells. The location of genes and regulatory elements within this chromosomal framework could help scientists better navigate their genomic research, establishing relationships between mutations and disease development.

13 Dec 2015

TBK1 protein plays vital role in the process of cell division

Moffitt Cancer Center researchers have found that a protein called TBK1 plays an important role in the process of cell division, especially at a stage called mitosis.

11 Dec 2015

Marqibo now available to leukemia patients through myTomorrows' Internet-based platform

myTomorrows (Amsterdam, the Netherlands), announced today that it has started a collaboration with Spectrum Pharmaceuticals, Inc. (Henderson, USA) to provide access to its liposome-encapsulated vincristine for treatment of Philadelphia chromosome negative acute lymphoblastic leukemia.

10 Dec 2015

Textbook view of the human cell cycle needs to be revised, shows new Danish research

Ground-breaking new Danish research has shown that the current scientific description of the human cell cycle needs to be revised. These findings could also lead to the development of new therapeutic approaches to target an Achilles' heel in different types of cancers.

9 Dec 2015

Amgen’s Phase 2 data supports safety, efficacy of BLINCYTO in ALL patients with minimal residual disease

Amgen today announced that new data from three Phase 2 trials support the efficacy and safety of BLINCYTO (blinatumomab) in adults with acute lymphoblastic leukemia (ALL).

8 Dec 2015

New approaches to treating leukemia, lymphoma and myeloma

New, highly targeted treatment approaches for leukemia, lymphoma, and myeloma to be presented today at the 57th American Society of Hematology Annual Meeting and Exposition represent a tremendous expansion of oral and intravenous therapy options for patients with blood cancers.

7 Dec 2015

Gene therapy shows promise in children with Wiskott-Aldrich syndrome

Researchers reported promising preliminary outcomes for the first four children enrolled in a U.S. gene therapy trial for Wiskott-Aldrich syndrome (WAS), a life-threatening genetic blood and immune disorder, at the 57th annual meeting of the American Society of Hematology (abstract #260).

7 Dec 2015

Second-line bosutinib offers ‘durable’ response for chronic phase CML patients

Four-year results for an ongoing study of second-line bosutinib indicate that the tyrosine kinase inhibitor offers long-term efficacy with manageable side effects for patients with chronic phase chronic myeloid leukaemia.

27 Nov 2015

Specific environmental influences can neutralize effect of genetic variant that increases childhood asthma risk

The effect of a widespread genetic variant that increases the risk for childhood asthma can be neutralized. A new study shows that young infants are particularly responsive to the positive influence of exposure to farm dust.

27 Nov 2015

Rutgers research reveals mechanism to prevent benign kidney tumor from becoming cancerous

Research from investigators at Rutgers Cancer Institute of New Jersey examining the inner workings of a rare non-cancerous (benign) kidney tumor has revealed a mechanism to prevent this type of tumor from becoming cancerous (malignant).

22 Nov 2015

FEC recognizes Rachel S. Weinerman for receiving 2015 Scientific Program Prize Paper Award

The Foundation for Embryonic Competence is pleased to recognize Dr. Rachel S. Weinerman, a clinical assistant professor, reproductive endocrinology and infertility at University Hospitals Case Medical in Cleveland, for receiving the 2015 Scientific Program Prize Paper Award at the 71st Annual American Society for Reproductive Medicine conference in Baltimore, Maryland on October 21, 2015.

12 Nov 2015

New method may extend use of noninvasive prenatal testing to detect chromosomal abnormalities

Researchers at the University of California, San Diego School of Medicine developed a method to expand the types of chromosomal abnormalities that noninvasive prenatal testing (NIPT) can detect. The study, published November 9 by Proceedings of the National Academy of Sciences, uses a semiconductor sequencing platform to identify small chromosomal deletions or duplications, such as occur in Cri du Chat Syndrome and DiGeorge Syndrome, with a simple blood test from the expectant mother.

10 Nov 2015

Two studies explore potential new blood tests for Alzheimer's disease

There is increasing evidence that the brain changes of Alzheimer's disease begin decades before memory and thinking problems occur, prompting the need for better methods of early detection for this progressive, fatal brain disease. Consequently, there is a growing school of thought that the most effective future Alzheimer's drug therapies will be administered to those who are at high risk of the disease before cognitive symptoms appear.

10 Nov 2015

Urinary biomarkers for bladder cancer diagnosis fall short of mark

Authors of a meta-analysis question the accuracy of urinary biomarkers for diagnosing the initial incidence or recurrence of bladder cancer.

4 Nov 2015

Patients with Down syndrome face additional challenge of early-onset dementia

Individuals with Down syndrome who survive into adulthood face the additional challenge of early-onset dementia, in which toxic amyloid plaques build up in the brain. The condition is strikingly similar to Alzheimer's disease, and as new work led by researchers at the Lewis Katz School of Medicine at Temple University shows, dementia in Down syndrome involves defects in a regulatory enzyme known as γ-secretase activating protein (GSAP), which also happens to malfunction in Alzheimer's disease.

3 Nov 2015

Rice scientists solve long-standing mystery about hemophilia protein

Rice University scientists have solved a long-standing mystery about where the body stores and deploys blood-clotting factor VIII, a protein that about 80 percent of hemophiliacs cannot produce due to genetic defects.