Down Syndrome PDF

Down Syndrome What is Down S yndrome? Down syndrome is the most common and best known of the chromosome disorders and is the single most common genetic cause of moderate intelacteal disability. Genetics of down syndrome 95% are trisomy 21 4% are translocation 2% are mosaics Nondisjunction In at leas...

Down Syndrome What is Down S yndrome? Down syndrome is the most common and best known of the chromosome disorders and is the single most common genetic cause of moderate intelacteal disability. Genetics of down syndrome 95% are trisomy 21 4% are translocation 2% are mosaics Nondisjunction In at least 95% of all patients, the Down syndrome karyotype has 47 chromosomes, with an extra copy of chromosome 21. This form of down syndrome is caused by abnormal cell division during the development of the sperm cell or egg cell. Translocation Approximately 4% of Down syndrome patients have 46 chromosomes, one of which is a Robertsonian translocation between chromosome 21q and the long arm of one of the other acrocentric chromosomes (usually chromosome 14 or 22) Translocation Translocation occurs when part of the number 21 chromosome breaks off during cell division and attaches to another chromosome. While the total number of chromosomes in the cells remains 46, the presence of an extra part of the number 21 chromosome causes the features of Down syndrome. Mosaic Approximately 2% of Down syndrome patients are mosaic for two cell populationsone with a normal karyotype and one with a trisomy 21 karyotype. The phenotype may be milder than that of typical trisomy21 Mosaicism occurs when nondisjunction of the 21st chromosome takes place in one of the initial cell divisions after fertilization. When this occurs, there is a mixture of two types of cells, some containing 46 chromosomes and some containing 47. Those cells with 47 chromosomes contain an extra 21st chromosome How can we detect down syndrome? Karyotyping Chromosomal microarray analysis Genomic sequencing of chorionic villus or amniotic fluid cells. Is it inherited? Most of the time, Down syndrome isn't inherited. It's caused by a mistake in cell division during the development of the egg, sperm or embryo. Translocation Down syndrome is the only form of the disorder that can be passed from parent to child. However, only about 4% of children with Down syndrome have translocation. And only about half of these children inherited it from one of their parents. Risks factors Being carriers of the genetic translocation for Down syndrome Advancing maternal age. Having had one child with Down syndrome. Statistics : Approximately 1 child in 850 is born with Down fetuses of mothers 35 years of age or older are highly prone to have down syndrome Dysmorphic features Of Down syndrome (phenotype) : 1. Intellectual disability 2. Short in suture 3. Short neck 4. Loose skin on the nape 5. Short and broad hands 6. Flat nasal bridge 7. Low set ears 8. Protruding tongue 9. Slating eyes 10. Hypotonia Oral and Dental manifestation Delayed eruption and abnormal tooth formation, leading to crowded or misaligned teeth. Occlusion : The bridge of the nose, middle facial bones, and upper jaw are relatively smaller in size. In many cases, this causes a prognostic Class III occlusal relationship that contributes to the open bite. The incidence of mouth breathing is very high due to the small airway, which may cause a decrease in saliva with dry mouth. This reduces the natural cleansing that occurs in the oral cavity may contribute to the development of caries. Importance of Early Dental Intervention for Children with Down Syndrome 1 Prevent Oral Health Issues Early dental check-ups and preventive care can help identify and address potential oral health problems in children with Down syndrome before they become more serious. 3 Improve Overall Health Maintaining good oral health is crucial for the general well-being of children with Down syndrome, as it can impact their nutrition, speech development, and selfesteem. 2 Establish Positive Dental Habits Starting dental visits from a young age can help children with Down syndrome feel more comfortable and develop good oral hygiene habits that will last a lifetime. 4 Promote Independence With the right support and early intervention, children with Down syndrome can learn to independently manage their oral care, fostering greater independence and selfconfidence. Is there a cure for Down syndrome? Unfortunately, there is no cure. But treatment (physically and mentally) is available to help them reach their full potential. In some cases, in vitro fertilization (IVF) can prevent down syndrome by examining the fertilized egg and returning the healthy one into the womb. References 1. Centers for Disease Control and Prevention (CDC) - Down Syndrome: https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html National Institute of Child Health and Human Development (NICHD) - Down Syndrome: https://www.nichd.nih.gov/health/topics/down/conditioninfo/default Mayo Clinic - Down Syndrome: https://www.mayoclinic.org/diseases-conditions/down-syndrome/symptoms-causes/syc-20355977 Thompson and Thompson https://www.mayoclinic.org/diseases-conditions/down- https://dsahrc.org/about-down-syndrome/what-causes-ds https://www.massgeneral.org/children/down-syndrome/translocation-down-syndrome https://www.mayoclinic.org/diseases-conditions/down-syndrome/symptoms-causes/syc-20355977 https://www.cdc.gov/ncbddd/birthdefects/downsyndrome/data.html https://www.stanfordchildrens.org/en/topic/default?id=down-syndrome-trisomy-21-in-children-90-P02356 https://www.nichd.nih.gov/health/topics/down/conditioninfo/treatments https://www.worlddownsyndromeday.org/ https://www.careflex.co.uk/info-centre/blogs/world-downs-syndrome-day-2023/