Down syndrome is a inborn upset that is caused by a otiose chromosome. Downs syndrome is the most common cause of malformation and mental deceleration in an baby ( Frey 1206 ) . There are three different types of Down syndrome: Free trisomy 21 ( or Trisomy 21 ) , Translocation, and Mosaicism. In this paper I will be specifically concentrating on Trisomy 21. The fact that Down ‘s syndrome is caused by the being of another partial or whole excess 21st chromosome is the ground why it can besides be called Trisomy 21. As a consequence of holding three 21st chromosomes this would give a patient who has Trisomy 21 47 chromosomes, alternatively of a normal sum of 46 chromosomes. Within the United States there is an estimated 6,000 kids born with Down ‘s syndrome every twelvemonth ( Frey 1206 ) . Statistically this breaks down to about 1 out of every 800 babies that are born with Trisomy 21 ( Driscoll 2556 ) .
Down syndrome occurs during miosis. During this phase disjuncture would usually happen. Disjunction is when a brace of chromosomes are supposed to divide up and divide into two different cells ; nevertheless, in Down syndrome the whole brace of chromosomes goes to one cell and does non split. As a consequence, one cell will hold 24 chromosomes and the other will hold 22 chromosomes. This uneven distribution of chromosomes is called nondisjunction. If one of the gametes has an unnatural figure of chromosomes and unites with its opposite number during fertilisation, this will ensue in a fertilized ovum with an unnatural figure of chromosomes. One of the gametes has two 21st chromosomes and its opposite number has one. When these unite and fertilise, they result in the fertilized ovum holding three 21st chromosomes. As a adult female ages, so does the frequence of nondisjunction ( Driscoll 2556 ) .
Even though Down ‘s syndrome is both a congenital and a chromosomal upset ; unlike some diseases which can non be detected upon physical scrutiny, Down ‘s syndrome is identifiable by many common outward physical features. The clinical manifestations of this disease are assorted minor and major differences in organic structure constellation such as a noticeable difference in facial characteristics which would include the undermentioned features: level looking face and span of the olfactory organ, a low set olfactory organ that is smaller in size, little caput, little oral cavity that causes the lingua to look abnormally big and to lodge out, Prunus dulcis shaped eyes that slant upward, rounded cheeks, a inclining under mentum, epicanthal creases ( which are excess creases of tegument near the nose part that can be seen at the inside corner of each oculus ) , and low set malformed ears ( Frey 1207 ) . More than half of those diagnosed with Down syndrome have hearing jobs. Manifestations of disease can besides be observed on the custodies of a patient with Down ‘s syndrome. The difference in manus characteristics that usually occur are: abnormally little and broad custodies, a distorted 5th finger, and a really noticeable simian fold which is a abnormally deep fold that is located across the centre of the patients thenar. The pess are besides normally affected and a big spread is normally discernible between the large and 2nd toe, besides unnatural folds can be seen on the colloidal suspensions of the patients ‘ pess. Other noticeable marks of Down ‘s syndrome are patients are normally shorter than normal tallness, have a shorter cervix, shorter limbs, hapless musculus tone, and are double-jointed ( Frey 1207 ) .
There are besides many clinical manifestations that can non be phenotypically expressed. Variations of intelligence degrees can be observed in Down ‘s syndrome patients. Lower than mean cognitive abilities can be exhibited or minor to severe mental deceleration can besides happen. Gastrointestinal manifestations of Down syndrome affect about 5-7 % of Down Syndrome. Duodenal atresia, which is a obstructed duodenum, is the most common GI piece of land deformity. This frequently causes the babe to puke and impairs its ability to derive weight decently due to the fact that the babes nutrient is non go forthing the tummy and come ining the bowel for digestion decently. Heart defects are besides common in people diagnosed with Down syndrome. Atrial septate defects, ventricular septal defects, and Tetralogy of Fallot are some of the bosom defects that often accompany Down syndrome. Patients with Down syndrome besides have an increased opportunity of developing hearing loss, ocular jobs, pneumonia, thyroid jobs ( most normally hypothyroidism ) , ear infections, and other assorted types of infections. Down syndrome patients besides have an increased hazard of developing leukaemia. They are 20 times more likely to develop leukaemia ( Frey 1207 ) .
Prenatal showing can be done to assist name if the foetus has Down syndrome. Both noninvasive showing trial and invasive diagnostic testing are available ; nevertheless, testing trials are less accurate than diagnostic testing. If the anticipating female parent wants a unequivocal reply than “ she may make up one’s mind to short-circuit showing and take either chorionic-villus sampling at 10-12 hebdomads gestation or amniocentesis between 15-20 hebdomads ‘ gestation ” ( Driscoll 2561 ) . Noninvasive and invasive trials are done so that the parent ( s ) can either get down preparing for a babe with Down syndrome or safely end the gestation ( Frey1209 ) .
One of the noninvasive showing trials that can be done is serum testing trials, which would be performed in the 2nd trimester. This trial measures different biochemical markers and is sometimes referred to as quadruplicate showing. This trial “ has a sensing rate of 80 % for Trisomy 21 ” and is soon “ the most common showing trial performed between 15 and 22 hebdomads ‘ gestation ” ( Driscoll 2557 ) . The quadruplicate screening trial is done to mensurate the degrees of alphafetoprotein, human chorionic gonadotrophin ( human chorionic gonadotropin ) , inhibin A, and unconjugated estriol. In Trisomy 21 characteristically low maternal degrees of alpha-fetoprotein and unconjugated estriol can be seen and high degrees of inhibin A and human chorionic gonadotropin are detected.
Chorionic-villus sampling and amniocentesis are two types of invasive diagnostic testing that may be used to assist name Down syndrome prenatally ( Driscoll 2559 ) . During chorionic-villus trying a little tubing is inserted into the womb to obtain a little sample of the placenta. Amniocentesis is a process where a thin long acerate leaf is used to retreat amnionic fluid from the amnionic pouch ( Frey 1209 ) . Although these two types of trials are more invasive they are more accurate and have a comparatively low rate of gestation loss ( Driscoll 2559 ) . There is a somewhat increased hazard of foetal loss with chorionic-villus trying than with amniocentesis ” ( Driscoll 1472 ) . Contemporary rates of gestation loss after ultrasound-guided amniocentesis are lower than the rate of 1 per 200 gestations ( 0.5 % ) ” and “ rates of foetal loss associated with chorionic-villus sampling are about 1 % higher than rates associated with amniocentesis ” ( Driscoll 2559 ) . Although there is more of a hazard factor when proving for Down Syndrome by agencies of Amniocentesis and Chorionic-villus sampling, they are more effectual than noninvasive methods because these trials provide unequivocal reply by agencies of Karyotyping.
Down syndrome is normally already the suspected diagnosing for those who have undergone antenatal testing. Besides at birth when the physical marks of Down syndrome can be seen, the baby so undergoes familial proving to verify that they have Trisomy 21. Familial testing can be done via tissue sample or blood sample. The sample of tissue or blood is used to obtain a karyotype, a image of the chromosomes paired and arranged by side and form, of the baby ‘s chromosomes. A karyotype done to prove for Trisomy 21 would uncover that there is an excess chromosome 21 ( Frey 1208 ) .
Down syndrome is a non-curable disease, therefore there is no intervention available. However, the secondary complications that patients see due to Down syndrome are the symptoms that can be treated. For illustration, hearing damage is frequently treated with hearing AIDSs. Ocular jobs can be corrected with spectacless or surgery ( Royston 20 ) . Duodenal atresia and bosom defects are treated by surgery ( Frey 1208 ) .
One manner that physicians do seek to forestall the happening of Down syndrome is that they refer twosomes fixing to hold babes to a familial counsellor ( Frey 1209 ) . The counsellor informs the twosome that the hazard of holding a babe with Down syndrome additions as the female parent ‘s age increases ; nevertheless, the bulk of babies with Trisomy 21 are born to adult females younger than 35 old ages of age ( Driscoll 1471 ) . Besides, antenatal testing may help in naming whether the foetus has Trisomy 21 or non. This advanced information presents the anticipating parents an chance to take what result is best for them. The anticipating parent ( s ) may take to get down be aftering on how to care for an baby with Down ‘s syndrome or a safe abortion of the foetus is besides another option that is made available ( Frey 1209 ) .
The forecast for patients with Down syndrome varies due to the fact that non all Down syndrome patients will be afflicted with the same complications. Some people diagnosed with Down syndrome, depending on the badness of the disease, are able to work, travel to school, and unrecorded about wholly independently. “ Provided they are helped and supported, either by their households or by societal services, people with Down syndrome can populate the same sort of life as everybody else ” ( Royston 37 ) . When you look in footings of the generative ability of work forces and adult females affected with Down syndrome an huge difference can be seen. Men about ever are unfertile, which enables them to hold kids. In contrast, adult females affected with Down syndrome have the ability to hold progeny ; nevertheless, approximately 50 % of babies born to a female parent with Down syndrome will be diagnosed with Down syndrome every bit good ( Frey 1208 ) . Age 50-55 is the mean age of decease for a individual diagnosed with Down syndrome ( Frey 1208 ) . 80 % of those diagnosed with Down syndrome live to the age of 60 or older ( Driscoll 2557 ) .