down syndrome Presentation. providing basic knowledge about down syndrome and its causes and management

ppt on down syndrome

1. Down syndrome By- Romel Solanki (Group - 2) Lecturer- Elene Petriashvilli

2. Introduction Down syndrome was first described by an English physician John Langdon Down in 1866, but its association with chromosome 21 was established almost 100 years later by Dr. Jerome Lejeune in Paris. It is the presence of all or part of the third copy of chromosome 21 which causes Down syndrome, the most common chromosomal abnormality occurring in humans. It is also found that the most frequently occurring live born aneuploidy is trisomy 21 that causes this syndrome.

3. Etiology The majority of patients with Down syndrome have an extra copy of chromosome 21. There are different hypothesis related to genetic basis of Down syndrome and association of different genotypes with the phenotypes. Among them is gene dosage imbalance in which there is an increased dosage or number of genes of Hsa21, which results in increased gene expansion. 3

4. Clinical Features Different clinical conditions are associated with Down syndrome as different systems are affected by it. These patients have a wide array of signs and symptoms like intellectual and developmental disabilities or neurological features, congenital heart defects, gastrointestinal (GI) abnormalities, characteristic facial features, and abnormalities.

5. A cropped photo of the eyes of a baby with Down Syndrome. Brushfield spots are visible between the inner and outer circle of the iris.  Flat appearing face Small head Small mouth which cause s the tongue to fall out making it seem large Upward slan ting eyes Rou nd cheeks We ak, floppy muscles(hypotonia) Wide hands, small ears Short height Signs and symptoms

6. Evaluation 6 There are different methods used for the prenatal diagnosis of Down syndrome. Ultrasound between 14 and 24 weeks of gestation can be used as a tool for diagnosis based on the soft markers like increased nuchal fold thickness, small or no nasal bone and large ventricles. Amniocentesis and chorionic villus sampling had widely been used for the diagnosis, but there is a small risk of miscarriages between 0.5% to 1%. A relatively new method called as paralogue sequence quantification (PSQ) uses the paralogue sequence on Hsa21 copy number. It is a PCR based method that uses the paralogue genes to detect the targeted chromosome number abnormalities which are known as paralogue sequence quantification.

7. Congenital Cardiac Defects (CHD) The most common cardiac defect associated with Down syndrome is an atrioventricular septal defect (AVSD), and this defect makes up to 40% of the congenital cardiac defects in Down syndrome. It is said to be associated with the mutation of the non-Hsa21  CRELD1  geneThe second most common cardiac defect in Down syndrome is a ventricular septal defect (VSD), which is seen in about 32% of the patients with Down syndrome. Together with AVSD, these account for more than 50% of congenital cardiac defects in patients with Down syndrome. 7

8. 8 Neurologic Disorders The risk of developing early-onset Alzheimer disease is significantly high in patients with Down syndrome with 50% to 70% of patients developing dementia by the age of 60 years. Five percent to 13% of children with Down syndrome have seizures, out of that, 40% will have seizures before their first birthday, and in these cases, the seizures are usually infantile spasms. Down syndrome children with infantile spasm do respond better to antiepileptics as compared to other kids with the same, and therefore, early intervention and treatment improve the developmental outcome. Lennox-Gestaut syndrome is also seen to be more prevalent in children with Down syndrome when it does occur, has a late onset, and is associated with reflex seizures along with an increased rate of EEG abnormalities. Forty percent of patients with Down syndrome develop tonic- clonic or myoclonic seizures in their first 3 decades. Dementia occurs more commonly in patients older than 45 years of age with Down syndrome, and about 84% are more prone to develop seizures. The seizures in these patients are related to the rapid decline in their cognitive functions.

9. diagnosis 9 Congenital hypothyroidism Mosaic trisomy 21 syndrome Partial trisomy 21(or 21q duplication) Robertsonian trisomy 21 Trisomy 18 Zellweger syndrome or other peroxisomal disorders

10. prognosis Presentation title 10 With the recent advances in the medical practice, development of surgical techniques for the correction of congenital disabilities and improvement in general care there has been a tremendous increase in the survival of infants and life expectancy of patients with Down syndrome. A Birmingham (United Kingdom) study done almost 60 years ago showed that 45% of the infants survived the first year of life, and only 40% would be alive at 5 years. A later study conducted about 50 years after that showed 78% of patients with Down syndrome plus a congenital heart defect survived for 1 year, while the number went up to 96% in patients without the anomalies. This rise in the life expectancy of these patients should continue to rise significantly because of the developments in medical science. Healthcare facilities aim to provide proper and timely management to these patients and to help them to have a fulfilled and productive life.

11. Treatment / Management 11 P atients should have their hearing and vision assessed and as they are more prone to have a cataract, therefore timely surgery is required. Thyroid function tests should be done on a yearly basis and if deranged should be managed accordingly. A balanced diet, regular exercise, and physical therapy are needed for the optimum growth and weight gain, although feeding problems do improve after the cardiac surgery. Other specialties involved include a developmental pediatrician , pediatric pulmonologist, gastroenterologist, neurologist, neurosurgeon, orthopedic specialist, child psychiatrist, physical and occupational therapist, speech and language therapist, and audiologist. Parental education is one of the foremost aspects regarding the management of Down syndrome, as parents need to be aware of the different possible conditions associated with it so that they can be diagnosed and treated appropriately. Treatment is basically symtomatic and complete recovery is not possible. This Photo by Unknown Author is licensed under CC BY-NC-ND

12. 12 The management of patients with Down syndrome is an interprofessional endeavor. Newborns with suspicion of Down syndrome, should have a karyotyping done to confirm the diagnosis. The family needs to be referred to the clinical geneticist for the genetic testing and counseling of both the parents. While life span has increased over the past 3 decades, these indivduals still have a shorter life expectancy compared to healthy individuals. Hence their medical treatment and caretaking should be done properly,

13. References Holmes G. Gastrointestinal disorders in Down syndrome. Gastroenterol Hepatol Bed Bench. 2014 Winter;7(1):6-8.  Gardiner K, Herault Y, Lott IT, Antonarakis SE, Reeves RH, Dierssen M. Down syndrome: from understanding the neurobiology to therapy. J Neurosci .  Antonarakis SE, Lyle R, Dermitzakis ET, Reymond A, Deutsch S. Chromosome 21 and down syndrome: from genomics to pathophysiology Pritchard MA, Kola I. The "gene dosage effect" hypothesis versus the "amplified developmental instability" hypothesis in Down syndrome. J Neural Transm Suppl. Holland AJ, Hon J, Huppert FA, Stevens F. Incidence and course of dementia in people with Down's syndrome: findings from a population-based study. J Intellect Disabil   Asim A, Kumar A, Muthuswamy S, Jain S, Agarwal S. "Down syndrome: an insight of the disease". J Biomed Sci.  13

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