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Chromosomal abnormalities
Chromosomal abnormalities A problem with the chromosomes - either inherited or caused by a mutation - that leads to disorders such as Down syndrome. An estimated half of all first-trimester miscarriages are due to chromosomal abnormalities too severe for the fetus to live.
RELATED TERMS--------------------------------------
Chromosomes
Filaments of genetic material in every cell nucleus that are made up of genes and that transmit genetic information from one generation of cells to the next.
Mutation
A change in DNA that alters a gene and thus the gene's product, leading in some cases to deformity or disease. Mutations can occur spontaneously during cell division or can be triggered by environmental stresses, such as sunlight, radiation, and chemicals.
Syndrome
A grouping of signs and symptoms, based on their frequent co-occurrence, that may suggest a common underlying pathogenesis, course, familial pattern, or treatment selection.
Fetus
The stage of human development from 10 weeks' gestation until birth.
SIMILAR TERMS--------------------------------------
Chromalbin
Chromalbin is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): albumin chromated cr-51 serum.
Chromatic adaptation technique
Used to identify receptor inputs. An adapting light is chosen such that it affects the response to one of the inputs to a cell far more than the other. The cells response is selectively desensitized so that the cell is largely driven by the other input. This way the response properties of the cell can now be studied in relative isolation.
Chromatids
The daughter strands of a duplicated chromosome joined together by a centromere.
Chromatin
The nucleoprotein material of chromosomes. Chromatin is essentially the substance of chromosomes. It is made up of DNA attached to a protein structure, together with chromosomal RNA. Chromatin exists in two states, euchromatin and heterochromatin, with different staining and functional properties.
Chromatin remodeling
Dynamic structural changes to the chromatin occurring throughout the cell division cycle. These changes range from the local changes necessary for transcriptional regulation to global changes necessary for chromosome segregation. Chromatin remodeling is an epigenetic phenomenon.
Chromatography, gas (GC)
A type of automated chromatography (a technique used to separate mixtures of substances) in which the mixture to be analyzed is vaporized and carried by an inert gas through a special column and thence to a detection device. The special column can contain an inert porous solid (in gas-solid chromatography) or a liquid coated on a solid support (in gas-liquid chromatography). The basic aim with GC is to separate each component that was in the mixture so that it produces a different peak in the detection device output which is graphed on a chart recorder. GC is a valuable tool in biochemistry (and other fields of chemistry, as in the analysis of perfumes).
Chromatophobia
An abnormal and persistent fear of money. Sufferers experience undue anxiety even though they realize their fear is irrational. They worry that they might mismanage money or that money might live up to its reputation as "the root of all evil."
Chromesthesia
A type of synesthesia in which which a nonvisual stimulus causes the individual to perceive color. Color hearing is a form of chromesthesia. In color hearing a musical tone elicits a color. One well-studied case involved an art teacher who had a range of consistent linkages between tone and color. For her, high octaves tended to evoke a lighter color value, while lower octaves evoked a darker color value. And rapid major chord tone sequences elicited rapid flashes of colors, "somewhat like fireworks exploding."
Chromic chloride
Chromic chloride is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): chromic chloride.
Chromic chloride in plastic container
Chromic chloride in plastic container is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): chromic chloride.
Chromitope sodium
Chromitope sodium is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): sodium chromate, cr-51.
Chromosomal mosaicism
A chromosomal pattern in which some cells of the body have the standard number of chromosomes (46,XX or 46,XY), and others have more or less, as in 45,X/46,XY (a mosaic variety of Turner's syndrome); or 46,XY/47,XXY (a mosaic variety of Klinefelter's syndrome), and many others.
Chromosome
A structural unit within a eukaryotic nucleus that carries genes. A chromosome consists of a long, continuous strand of DNA and associated proteins.
Chromosome 1
The largest human chromosome, comprising approximately 10% of the human genome. Chromosome 1 contains over 240 million base pairs and over 3000 genes including the UROD gene for porphyria cutanea tarda, the GBA gene for Gaucher disease, the GLC1A gene for glaucoma, the HPC1 gene for prostate cancer, and the PS2 gene for Alzheimer disease.
Chromosome 11 childhood leukemia
A new type of childhood leukemia in which a piece of chromosome 11 has been translocated (broken off and attached itself to another chromosome). Children with this type of leukemia have a particularly poor prognosis (outlook). They do not respond at all well to the standard therapies for ALL (acute lymphoblastic or lymphocytic leukemia) and often suffer from early relapse after chemotherapy. Children with chromosome 11 translocation leukemia have gene expression profiles that are different from the profiles of other acute leukemias such as ALL and acute myeloid leukemia.
Chromosome 2
The second largest chromosome in the human genome. Chromosome 2 contains over 240 million base pairs and more than 2500 genes, including the ETM2 gene for essential tremor, the MSH2 and MSH6 genes for colon cancer, and the PAX3 gene for Waardenburg syndrome.
Chromosome 3
One of the largest human chromosomes, comprising approximately 6.5% of the human genome. Chromosome 3 has between 1,100 and 1,500 genes of the estimated 30,000 to 40,000 genes in the human genome. Among the genes on chromosome 3 are the HGD gene for alkaptonuria, the BTD gene for biotinidase deficiency, the CPOX gene for hereditary coproporphyria, the MLH1 gene for hereditary nonpolyposis colorectal cancer (HNPCC), the ZNF9 gene for type 2 myotonic dystrophy, the TMIE gene for an autosomal recessive form of nonsyndromic deafness, and the BCCB gene for propionic acidemia.
Chromosome 4p- syndrome
The 4p- syndrome or Wolf-Hirschhorn syndrome, is a chromosome disorder due to partial deletion of the short (p) arm of chromosome 4. It is, therefore, also called the 4p- syndrome. Features of the syndrome include midline defects with a scalp defect, widespaced eyes, broad or beaked nose, oral facial clefts (cleft lip/palate); low simple ears with a dimple in front of the ear; small &/or asymmetrical head; heart defects; and seizures (that tends to diminish with age). There is severe to profound developmental and mental retardation. Some patients do learn to walk with or without support and some achieve sphincter control (by day). There is usually very slow progress in development.
Chromosome 5q- syndrome
A blood disorder due to the loss of part of the long (q) arm of chromosome 5 in myeloid (bone marrow) cells, causing refractory (treatment-resistant) anemia, and myelodysplastic syndrome that is generally associated with a good prognosis but on occasion may lead to AML (acute myeloid leukemia).
Chromosome band
One of the transverse bands produced on chromosomes by differential staining techniques. Depending on the particular staining technique, the bands are alternating light and dark or fluorescent and nonfluorescent.
Chromosome banding
The treatment of chromosomes to reveal characteristic patterns of horizontal bands like bar codes. The banding patterns lend each chromosome a distinctive appearance so the 22 pairs of human nonsex chromosomes and the X and Y chromosomes can be identified and distinguished without ambiguity. Banding also permits the recognition of chromosome deletions (lost segments), chromosome duplications (surplus segments) and other types of structural rearrangements of chromosomes.
Chromosome complement
The whole set of chromosomes for the species. In humans, the chromosome complement (which is also called the karyotype) consists of 46 chromosomes.
Chromosome disorder
An abnormal condition due to an abnormality of the chromosomes. For example, Down syndrome (the genetic abnormality featuring three chromosome 21s, instead of two, also referred to as trisomy 21) is a chromosome disorder.
Chromosome duplication
Part of a chromosome in duplicate. A particular kind of mutation involving the production of one or more copies of any piece of DNA, including sometimes a gene or even an entire chromosome. A duplication is the opposite of a deletion.
Chromosome inversion
A chromosome segment is clipped out, turned upside down and reinserted back into the chromosome. A chromosome inversion can be inherited and have come from one of the parents to a child. Or the inversion can appear for the first time in a child.
Chromosome inversion, paracentric
A basic type of chromosome rearrangement. A segment that does not include the centromere (and so is paracentric) has been snipped out of a chromosome, turned through 180 degrees (inverted), and inserted right back into its original location in chromosome. The feature that makes it paracentric is that both breaks are on the same side of the centromere so that the centromere (the point at which the chromosome attaches to the spindle) is not affected. Any chromosome inversion can be inherited and have come from one of the parents to a child. Or the inversion can appear for the first time in a child. An inversion can be "balanced", meaning that it has all the genes present in the normal uninverted chromosome. Or an inversion can be "unbalanced", meaning that genes been have deleted (lost) or duplicated. A balanced inversion in a child causes no problems. An unbalanced inversion is abnormal and is often associated with problems such as development delay (and later, mental retardation) and multiple congenital anomalies (birth defects). Inversions can also be acquired in a body cell (a somatic cell) and be a step involving that cell in a precancerous and cancerous process.
Chromosome inversion, pericentric
A basic type of chromosome rearrangement in which a segment that includes the centromere (and so is pericentric) has been snipped out of a chromosome, turned through 180 degrees (inverted), and inserted back into its original location in chromosome. The feature that makes it pericentric is that both breaks are on either side of the centromere (the point at which the chromosome attaches to the spindle). Any chromosome inversion can be inherited and have come from one of the parents to a child. Or the inversion can appear for the first time in a child. An inversion can be "balanced", meaning that it has all the genes present in the normal uninverted chromosome. Or an inversion can be "unbalanced", meaning that genes been have deleted (lost) or duplicated. A balanced inversion in a child causes no problems. An unbalanced inversion is abnormal and is often associated with problems such as development delay (and later, mental retardation) and multiple congenital anomalies (birth defects). Inversions can also be acquired in a body cell (a somatic cell) and be a step involving that cell in a precancerous and cancerous process.
Chromosome, acentric
A fragment of a chromosome (one of the microscopically visible carriers of the genetic material DNA) that is lacking a centromere (the "waist" of the chromosome essential for the division and the retention of the chromosome in the cell) and so is lost when the cell divides.
Chromosome, acrocentric
A chromosome (one of the microscopically visible carriers of the genetic material DNA) with its centromere (the "waist" of the chromosome) located quite near one end of the chromosome. The "acro-" in acrocentric comes from the Greek "akron" meaning "the end." Humans have 5 pairs of acrocentric chromosomes. Down syndrome (trisomy 21) is due to an extra acrocentric chromosome, namely chromosome 21.
Chromosome, dicentric
An abnormal chromosome (a microscopically visible carrier of the genetic material DNA) with two centromeres rather than the normal one. The centromere is essential for the division of the chromosome. A dicentric chromosome is twice tethered and so is pulled in opposite directions when the cell divides and this causes the chromosome to form a bridge and then break. Dicentric chromosomes are a cause of chromosome instability.
Chromosome, marker
An abnormal chromosome that is distinctive in appearance but not fully identified. A marker chromosome is not a "marker" of a specific disease. It is a marker chromosome merely in the sense that it can be distinguished under the microscope from all of the normal human chromosomes. For example, the fragile X chromosome was once called the marker X.
Chromosome, metaphase
A chromosome in the stage of the cell cycle (the sequence of events in the life of a cell) when a chromosome is most condensed and easiest to distinguish and so to study. Metaphase chromosomes are often chosen for karyotyping and for chromosome analysis because they are readily seen.. However, chromosomes in metaphase can be so condensed and scrunched up that it is difficult to make out much in the way of detail. More distended chromosomes (in prometaphase or prophase) are therefore sometimes selected for study when fine details are important.
Chromosome, X
The sex chromosome found twice in normal females and once, along with a Y chromosome, in normal males. The complete chromosome complement consisting of 46 chromosomes including the two sex chromosomes is conventionally written as 46,XX for females and 46,XY for males. The X chromosome carries hundreds of genes. Few, if any, of them have anything to do with sex. It is thought that the X and Y chromosomes evolved from an ancient pair of autosomal (nonsex) chromosomes and that the X chromosome retains much of its old autosomal information.
Chromosomes
Filaments of genetic material in every cell nucleus that are made up of genes and that transmit genetic information from one generation of cells to the next.
Chromosomes in multiple miscarriages
Couples who have had more than one miscarriage (spontaneous abortion) have about a 5% chance that one member of the couple is carrying a chromosome translocation responsible for the miscarriages.
Chromostereopsis
The optics of the eye are such that short wavelengths are refracted slightly more than long wavelengths creating a positional disparity on the retina. When viewed by two eyes a stereoscopic disparity is obtained. This is termed Chromostereopsis or Chromatic Stereopsis
Chronic
Ongoing or recurring. Chronic medical conditions include diabetes, epilepsy, and chronic fatigue syndrome.
Chronic bacterial prostatitis
Longstanding bacterial infection of the prostate gland superimposed on a defect in the prostate. (The prostate is a small organ below the bladder which surrounds the urethra, the tube that carries urine down from the bladder.) The symptoms can include low back pain, discomfort in the perineum (the area between the anus and the genitalia), testicular pain and, if the infection spreads to the bladder, mild pain or burning on urination (dysuria) and frequent and urgent need to urinate (frequency and urgency). The presence of white blood cells and bacteria in the urine attests to the fact that the urinary tract is infected with bacteria. The defect in the prostate is the focal point for the persistent infection. Effective treatment requires identification and correction of this defect before antibiotics can be effective.
Chronic bronchitis
Defined clinically as a daily cough with production of sputum for 3 months, two years in a row. In chronic bronchitis, there is inflammation and swelling of the lining of the airways that lead to narrowing and obstruction of the airways. The inflammation stimulates production of mucous (sputum), which can cause further obstruction of the airways. Obstruction of the airways, especially with mucus, increases the likelihood of bacterial lung infections.
Chronic disease
A disease that persists for a long time.
Chronic fatigue syndrome
A debilitating and complex disorder characterized by profound fatigue of six months or longer duration that is not improved by bed rest and that may be worsened by physical or mental activity. Persons with chronic fatigue syndrome (CFS) most often function at a substantially lower level of activity than they were capable of before the onset of illness. In addition to these key defining characteristics, patients report various nonspecific symptoms, including weakness, muscle pain, impaired memory and/or mental concentration, insomnia and post-exertional fatigue lasting more than 24 hours. In some cases, CFS can persist for years.
Chronic Fatigue Syndrome (CFS)
Chronic Fatigue Syndrome is a chronic illness that affects many body systems and their functions, particularly the nervous and immune systems. The illness can cause extreme fatigue, muscle pain, memory loss and poor concentration.
Chronic illness
An illness that persists for a long period of time.
Chronic leukemia
Cancer of the blood cells (leukemia) that progresses slowly.
Chronic myelogenous leukemia
A chronic malignant disease in which too many white blood cells belonging to the myeloid line of cells are made in the bone marrow. Early symptoms of this form of leukemia include fatigue and night sweats. The disease is due to the growth and evolution of an abnormal clone of cells containing a chromosome rearrangement known as the Philadelphia (or Ph) chromosome. Chronic myelogenous leukemia is commonly called CML. It is also known as chronic myelocytic leukemia and chronic granulocytic leukemia.
Chronic obstructive lung disease (COLD)
Any disorder that persistently obstructs bronchial airflow. COLD mainly involves two related diseases -- chronic bronchitis and emphysema. Both cause chronic obstruction of air flowing through the airways and in and out of the lungs. The obstruction is generally permanent and progresses (becomes worse) over time.
Chronic Obstructive Pulmonary
Any disorder that persistently obstructs bronchial airflow. COPD mainly involves two related diseases -- chronic bronchitis and emphysema. Both cause chronic obstruction of air flowing through the airways and in and out of the lungs. The obstruction is generally permanent and progresses (becomes worse) over time.
Chronic obstructive pulmonary disease
A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include chronic bronchitis and pulmonary emphysema.
Chronic obstructive pulmonary disease (COPD)
A progressive lung disease process characterized by difficulty breathing, wheezing, and a chronic cough. Complications include bronchitis, pneumonia, and lung cancer.
Chronic otitis externa
Chronic inflammation of the skin lining the external ear canal leading to the ear drum. Can be caused by a number of problems including bacterial infection, a chronic skin disorder (eczema or seborrhea), fungus (Aspergillosis), chronic irritation (hearing aids, Q-tips), allergy, chronic drainage from middle ear disease, a tumor (rare), or it may simply be due to a nervous habit of frequently scratching the ear.
Chronic pain
Chronic pain is medically defined as pain that has lasted 6 months or longer.This constant or intermittent pain has often outlived its purpose, as it does not help the body to prevent injury.It is often more difficult to treat than acute pain.
Chronic pancreatitis
A form of pancreatitis in which there is persistent inflammation of the pancreas.
Chronic phase
Refers to the early stages of chronic myelogenous leukemia. The number of immature, abnormal white blood cells in the bone marrow and blood is higher than normal, but lower than in the accelerated or blast phase.
Chronic progressive external ophthalmoplegia
Slowly progressive paralysis of certain eye muscles. Chronic progressive external ophthalmoplegia is abbreviated CPEO.
Chronic renal failure
Slow progressive loss of kidney function over the span of years, resulting in permanent kidney failure. Chronic kidney disease is common and may go undiagnosed until the process is far advanced and renal failure is on the horizon. People with permanent kidney failure need dialysis or a transplanted kidney to do the work of their failed kidneys.
Chronic tamponade
A situation in which a chronic excess of fluid inside the pericardial sac and thickening of the pericardial sac progressively compress the heart and impair its performance. The excess fluid in the pericardial sac acts to constrict the heart. Here the outpouring of fluid within the pericardial sac is slowly smashing into the heart.
Chronic Venous Insufficiency
Damaged valves in the veins or a blood clot in the leg may cause ongoing swelling, blood pooling in the legs, and if untreated, discomfort and ulceration.
Chronic wasting disease
A transmissible spongiform encephalopathy (TSE) of North American deer and elk, a progressive neurodegenerative disorder that produces spongiform changes in the brain and chronic weight loss leading to the death of these animals. There is no known relationship between chronic wasting disease (CWD) and any other TSE of animals or people.
Chronicity
Characterized by long duration. The state of being chronic.
Chronophilia
One of a group of paraphilias of the stigmatic/eligibilic type in which the paraphile's sexuoerotic age is discordant with his/her actual chronological age and is concordant with the age of the partner, as in, respectively, infantilism or nepiophilia; juvenilism or pedophilia; adolescentilism or ephebophilia (Lolita syndrome); and gerontalism or gerontophilia.
Chronulac
Chronulac is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): lactulose.
PREVIOUS AND NEXT TERMS--------------------------------------
Cervical mucus
Vaginal discharge that changes in consistency throughout a woman's monthly cycle, resembling raw egg white around ovulation. Many women check the consistency of their cervical mucus along with their basal body temperature to chart fertility.
Cervical mucus method
A natural birth control method accomplished by timing intercourse according to the consistency of the woman's cervical mucus. Mucus similar to raw egg white signifies ovulation, when a woman is most fertile, while thick and cloudy mucus indicates a time when conception is less likely.
Cervicitis
An inflammation of the cervix, cervicitis can be caused a bacterial or viral infection or irritation of the cervix during childbirth or surgery. Symptoms include an abonormal discharge, pain, or spotting.
Cesarean section
A surgical procedure in which a baby is delivered through an incision in the abdomen and uterus. Used when a woman can't give birth vaginally or if the baby is in distress.
Chicken pox
A mild, highly contagious virus characterized by itchy fluid-filled blisters all over the body that can lead to complications if the blisters become infected. A vaccine is available.
Chromosomal abnormalities
Chronic
Ongoing or recurring. Chronic medical conditions include diabetes, epilepsy, and chronic fatigue syndrome.
Circumcision
The surgical removal of the sheath of skin (called a foreskin) that covers the head of the penis.
Cleft lip and palate
A birth defect in which the lip or the lip and palate (roof of the mouth) do not grow together. Can be repaired with surgery, usually performed within the first year after birth.
Club foot
A birth defect in which the foot or ankle is deformed. Twice as common in boys, and affecting one in every 400 births, club foot is treated with exercises, splinting, or, in severe cases, surgery.
Clubfoot
A congenital deformed or distorted foot. May respond to exercises and/or surgery.
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