Down’s Syndrome Reilly Flodin David Kim
Inheritance • Down’s syndrome is neither a dominant or recessive genetic disease. • It is also known as Trisomy 21, for a specific reason. • Down’s syndrome occurs due to the occurrence of a meiotic mishap. • Although sole chance is a possibility, it is the least likely.
Chromosomal Abnormality Description • Occurring about 95% of the time is meiotic nondisjunction. • Essentially, a gamete (either from the father or mother) cell that carries an extra copy of chromosome 21 will combine with a normal gamete from the other parent, which translates to it possessing 24 chromosomes. • The resulting gamete embryo will then have 47chromosomes as opposed to 46, with the extra chromosome being a detrimental copy of chromosome 21. • The duplication of a segment on the chromosome is also possible, but very rare. It would result in the expression of specific Down’s syndrome physical or mental attributes.
The extra chromosome 21 is shown here. http://www.treatgene.com/wp-content/uploads/2009/11/21_trisomy_-_Down_syndrome1.png
Down’s syndrome prevalence in the population • As of December 2009, the disease has been found to occur in approximately 1 baby per 800 babies (.125%), or 5,400 babies per year in the United States. • From 1979 to 2003, the occurrence of Down’s syndrome annually has been recorded as increasing. - 31.1% increase- 9/10,000 live births 12/10,000 live births
Graph of the live birth prevalence for Down syndrome. blogs.downsed.org
Chances of passing on • A common study in Down’s syndrome for inheritance has been that of the mother’s age. • Studies have shown that as the mother ages, her egg cells become less potent than at her more youthful years. • This is evidenced by rates for the disease close to the national average (1/725) for women aged at 32, and women at the age of 49 having high rates of 1/12. • A scenario that has recently been looked into points to Down’s syndrome rates increasing with higher paternal age as well.
Graph depicting rising rates for rising maternal age. http://static.brazencareerist.com/pblog/DownsSyndromeGraph.gif
Diagnosis • Down’s syndrome is most always diagnosed prenatally, or before the child’s birth. • Many standard pre-natal screening procedures can detect Down’s syndrome early on. • These include but are not limited to:- Ultrasound- Amniocentesis- CVS- PUBS
This ultrasound test reveals offspring with Down’s syndrome. http://upload.wikimedia.org/wikipedia/commons/5/5e/T21.JPG
Physical symptoms • Microgenia (abnormally small chin) • Muscle hypotonia (poor muscle tone) • Flat nasal bridge • Mongoloid fold • Single palmar fold • Protruding or enlarged tongue • Short neck • White spots on iris • Excessive joint laxity in various parts of the body • Higher number of ulnar loop dermatoglyphs. • Congenital heart disease • Malignancies (such as leukemia) • Thyroid disorders • Infertility
Those with Down’s syndrome often exude similar physical characteristics. http://blogs.monografias.com/sistema-limbico-neurociencias/files/2010/03/down-syndrome.jpg
Life expectancy • As with all diseases, life expectancy varies widely depending on the severity of the Down’s syndrome in various individuals. • 75% of those with the disease will not survive before birth. • Of these, 15% are expected to die before one year of life. • The next 35% are expected to die sometime before 50. • The remaining 50% are expected to survive over 50 years of age.
treatment • First and foremost, there is no cure. • Primary treatment for any of the physical ailments are essential. • For the disease itself, regular check-ups/screenings, medications, surgery, and patient counseling are often the most effective modes for treatment. • Patience is preferable.
New research • There has been a push in focus for cognition, or the ability for individuals to communicate and learn with fluidity. • This includes research into discovering with more clarity various underlying causes and then creating treatments to help patients cope with their hardship. • Pharmaceutical and emotional therapies are being more extensively developed. • Somewhat inquisitive, but interaction with patients in order to observe behavioral characteristics have greatly assisted in the journey for a possible cure or treatment.
Everyday life/quality of life • Babies with Down’s syndrome are at greater risk of having congenital disorders. Some 40% of babies are born with serious congenital heart defects, but most can now be repaired by heart surgery during the first year or improve with time. A smaller number of babies have intestinal obstructions, which require surgery shortly after birth. Babies with Down’s syndrome tend to be less resistant to infections and need extra care during infancy and throughout life. They are also at greater risk for thyroid disorders and some other illnesses, most of which are easily treated. • By the time they reach their teenage years, most young people with Down syndrome are healthy and have similar healthcare needs to the rest of the population. • In middle to old age (beyond 40 years of age), adults with Down’s syndrome are at greater risk of developing Alzheimer disease.
Limitations • Some limitations include sensory impairments, hearing loss, vision, additional developmental and educational needs, social development and communication, speech impediment, and verbal short-term memory. All studies of the development of children with Down’s syndrome indicate that the children will progress more slowly than typically developing children and will have significant learning difficulties. In the first year of life, babies with Down’s syndrome show only slight delay in their social and communicative development. They smile just a week or so later than average and then are very interested in other people, communicating with smiles, coos and then babble, just like all infants. They then move on to using gestures (pointing, waving) to attract attention and ask for what they want a little later but essentially like all children.
Limitations Cont. • Verbal short-term memory skills seem to be less efficient and to develop more slowly in children with Down syndrome. In all children they influence language learning and speech processing abilities so activities that help to develop memory skills are important. • The other important medium through which they learn is play - play as we see it through childhood and then in leisure activities. Children with Down’s syndrome learn through play like everyone else, but they may benefit from more help. It may be important to demonstrate play activities and become a play partner in order to encourage play and exploration for the child with Down’s syndrome. Remember that they may not be understanding all the talk you use, but they are good at watching and learning by imitation.
Helpful Organizations for children with down’s syndrome • http://www.med.umich.edu/yourchild/topics/internetguide.htm • http://www.med.umich.edu/yourchild/topics/chronic.htm#adjust • http://www.k-state.edu/counseling/topics/relationships/dysfunc.html
Helpful Organizations for children with down’s syndrome Cont. • All of these websites have organizations that help families cope with their child having a disorder. They schedule groups for support and advice. Some of them even have websites that are open to telling your story and seeing others’. Families, education and healthcare professionals, and society as a whole, need to aim to offer people with Down’s syndrome normality first and foremost. Children with Down’s syndrome should receive the normal range of family stimulation, play, social experience and education opportunities as all other children. All people with Down’s syndrome should receive the same minimum standards of healthcare as all other people, supplemented with appropriate preventative management of their particular additional medical needs. The specific special activities targeted to help the child, such as signing or physiotherapy should be provided in addition to normal childhood experiences. They should therefore be provided in regular settings, alongside typically developing peers.
How is it possible for a cure to be found? • Medications can be used to treat certain conditions that someone may have with Down’s syndrome, but no cure has been discovered yet but there has been research on the increase of Down’s syndrome. The treatment consists of a common dietary supplement (EGCG). A family used EGCG and said that they’re 12-year-old son had Down’s syndrome and by taking this is helped significantly with his memory problems. • Chronic smoking is associated with a significant decrease in higher level brain function during middle age.
Works Cited • http://en.wikipedia.org/wiki/Down_syndrome • http://www.medicalnewstoday.com/articles/172493.php • http://pregnancy.about.com/cs/downsyndrome/l/bldownssyn.htm • http://www.webmd.com/infertility-and-reproduction/news/20030701/dad-age-down-syndrome • http://www.cdadc.com/ds/downsyndromelifeexpectancy.htm • http://dsresearch.stanford.edu/about/ • http://www.dsrtf.org/ • http://www.dsrf.org/research/research_publications/
Works cited cont. • http://dstoner.net/Math_Science/Downs.html • http://doctorwascher.com/Archives/11-30-08.htm • http://www.med.umich.edu/yourchild/topics/internetguide.htm • http://down-syndrome.emedtv.com/down-syndrome/treatment-for-down-syndrome-p2.html • http://www.down-syndrome.org/information/development/overview/?page=5 • http://kidshealth.org/kid/health_problems/birth_defect/down_syndrome.html