What is Chromosome 21?

mountain syndrome (DS) is a condition in which plain contractable visible causes delays in the way a child develops, and much leads to mental retardation. It affects 1 in every 800 babies born. The symptoms of put down syndrome brook diverge widely from child to child. While around kids with DS need a lot of medical attention, others lead very healthy and independent lives. though Down syndrome potentiometert be prevented, it fuel be chance oned before a child is born. The health problems that jackpot go along with DS can be treated, and there ar many resources within communities to help kids and their families who argon living with the condition.Norm in whollyy, at the time of conception a baby inherits genetic information from its p bents in the form of 46 chromosomes 23 from the mother and 23 from the father. In most cases of Down syndrome, however, a child gets an extra chromosome for a total of 47 chromosomes instead of 46. Its this extra genetic material that ca uses the forcible and cognitive delays associated with DS. Although no one knows for sure why DS occurs and theres no way to prevent the chromosomal error that causes it, scientists do know that women period 35 and older have a significantly higher insecurity of having a child with the condition.At age 30, for example, a woman has little than a 1 in 1,000 chance of conceiving a child with DS. Those odds increase to 1 in 400 by age 35. By 42, it jumps to about 1 in 60. How Does Down Syndrome Affect a kid? Kids with Down syndrome tend to sh atomic number 18 certain physical features such as a flat facial profile, an upward slant to the eyes, small ears, a single crease across the center of the palms, and an enlarged tongue. A twist around can usually tell if a newborn has the condition finished a physical exam. Low muscle tone and loose joints are also mark of children with DS, and babies in particular may seem particularly floppy. Though this can and often does improve over time, most children with DS typically obtain developmental milestones like sitting up, crawling, and walking posterior than other kids. At birth, kids with DS are usually of average size, exactly they tend to grow at a slower rate and await smaller than their peers. For infants, low muscle tone may contri plainlye to sucking and feeding problems, as well as constipation and other digestive issues. In toddlers and older children, there may be delays in lecturing and self-care skills like feeding, dressing, and toilet teaching.Down syndrome affects kids cognitive abilities in different ways, but most have mild to moderate mental retardation. Kids with DS can and do learn, and are capable of developing skills throughout their lives. They simply reach goals at a different pace which is why its important not to compare a child with DS with typically developing siblings or even other children with the condition. Kids with DS have a wide reaching of abilities, and theres no way t o tell at birth what they will be capable of as they grow up.Medical Problems Associated with Down Syndrome. While some kids with DS have no other health problems, others may possess a host of medical issues that require extra care. For example, half of all children born with DS also have congenital heart defects and are prone to developing pulmonary hypertension (high blood pressure in the lungs). A pediatric cardiologist can monitor these examples of problems, many of which can be treated with medication or surgery. Approximately half of all kids with DS also have problems with hearing and vision. Hearing loss can be related to fluid buildup in the inner ear or to structural problems of the ear itself.Vision problems commonly include amblyopia (lazy eye), near- or farsightedness, and an increase risk of cataracts. Regular evaluations by an audiologist and an ophthalmologist are necessary to detect and correct any problems before they affect a childs language and acquire skills. Other medical conditions that may occur more frequently in children with DS include thyroid problems, intestinal ab publicities, seizure disorders, respiratory problems, obesity, an change magnitude susceptibility to infection, and a higher risk of childhood leukemia. Fortunately, many of these conditions are treatable. What is Chromosome 21?According to wikipedia. org, Chromosome 21 is one of the 23 pairs of chromosomes in benevolents. batch normally have two copies of this chromosome. The trisomy of the 21 causes Down Syndrome. Chromosome 21 is the smallest human chromosome, spanning almost 47 million nucleotides (the building material of DNA) and representing about 1. 5 percent of the total DNA in stalls. The Human Genome Project proclaimed that they had determined the sequence of base pairs that make up this chromosome. Chromosome 21 was the mho human chromosome to be fully sequenced. Chromosome 21 likely contains mingled with cc and 400 genes.These include APP amyloid beta (A4) precursor protein (peptidase nexin-II, Alzheimer unsoundness) CBS cystathionine-beta-synthase CLDN14 claudin 14 HLCS holocarboxylase synthetase (biotin-(proprionyl-Coenzyme A-carboxylase (ATP-hydrolysing)) ligase) KCNE1 grand voltage-gated channel, Isk-related family, member 1 KCNE2 potassium voltage-gated channel, Isk-related family, member 2 LAD leukocyte adhesiveness deficiency (symbols are ITGB2, CD18, LCAMB) SOD1 superoxide dismutase 1, soluble (amyotrophic lateral sclerosis 1 (adult)) TMPRSS3 transmembrane protease, serine 3.Effects of Chromosome 21 The effects of chromosome 21 is best felt by the conditions that are associated with its lack or mutation. These include Cancer Rearrangements (translocations) of genetic material between chromosome 21 and other chromosomes have been associated with several types of cancer. For example, acute lymphoblastic leukemia (a type of blood cancer most often diagnosed in childhood) has been associated with a translocati on between chromosomes 12 and 21. Another form of leukemia, acute myeloid leukemia, has been associated with a translocation between chromosomes 8 and 21.Down Syndrome In a small percentage of cases, Down syndrome is caused by a rearrangement of chromosomal material between chromosome 21 and another(prenominal) chromosome. As a result, a person has the usual two copies of chromosome 21, improver extra material from chromosome 21 attached to another chromosome. These cases are called translocation Down syndrome. Researchers believe that extra copies of genes on chromosome 21 disrupt the course of normal development, causing the characteristic features of Down syndrome and the increased risk of medical problems associated with this disorder. intellectual Retardation Other changes in the number or structure of chromosome 21 can have a variety of effects, including mental retardation, delayed development, and characteristic facial features. In some cases, the signs and symptoms are sim ilar to those of Down syndrome. Changes to chromosome 21 include a missing segment of the chromosome in each cell (partial monosomy 21) and a circular structure called ring chromosome 21. A ring chromosome occurs when both(prenominal) ends of a broken chromosome are reunited.Alzheimers Disease. Duplication in starchy precursor protein (APP) locus (duplicated segment varies in length but includes APP) on Chromosome 21 was found to cause early on round familial Alzheimers disease (AD) in a french family set (Rovelet-Lecrux et al) and a dutch family set (Sleegers et al). Compared to AD caused by missense mutations in APP, the frequency of the AD caused by APP duplicates is significant. every the patients that have an extra copy of APP gene due to the locus duplication show AD with severe Cerebral amyloid angiopathy (CAA).