Down syndrome 18 week ultrasound 4d1/3/2024 ![]() In the United States in 1960 individuals with Down syndrome lived on average about 10 years while in 2007 individuals with Down syndrome lived to approximately 47 years of age 17.Ī 2003 study found that 78% of patients with Down syndrome and a congential cardiac defect survied their first year of life, compared to 98% of those without a congenital cardiac defect 18. Life expectancy for individuals with Down Syndrome has increased signigicantly due to a reduction in rates of institutionalization and improved medical care in the past several decades 17. These are discussed in detail in a separate article. Some of these are better discussed under individual features in the wide clinicopathological spectrum of the condition (listed above). The manifestations of Down syndrome are protean and can affect multiple systems. ![]() Significantly increased incidence of leukemia (although the individual may be protected against other solid organ tumors) Hypothyroidism ( congenital, subclinical or acquired autoimmune and non-autoimmune) " mickey mouse" pelvis with flaring of iliac wings In particular, defects affecting the endocardial cushion are common:Ītrioventricular septal defect (AVSD): considered the commonest cardiac defect associated with Down syndromeĪtlantoaxial subluxation and atlantooccipital instability 2,3 Intellectual disability: average IQ ranges ~50-70Ĭongenital heart disease affects ~40%. semicircular canal dysplasia and dehiscence, narrowed internal acoustic canal, cochlear nerve canal stenosis, enlarged vestibular aqueduct 12 Hearing loss from inner ear anomalies, e.g. Hippocampal volume loss: independent of age/dementia 4 Structurally evident abnormalities include:Īlzheimer disease developing in virtually all patients older than 40 years Clinicopathological spectrum Neurological manifestationsĬognitive disability and epilepsy are the most common neurological manifestations 8. Very rarely (~2%) some individuals have mosaic trisomy 21. Maternal non-disjunction accounts for ~95% of such cases.Īn alternative chromosomal abnormality that results in the syndrome involves Robertsonian translocation of paternal chromosomal material, such that the overall number of chromosomes remains the same. failure of a chromosome pair to separate during meiosis, so that both go to one daughter cell, and none to the other). Thus, the individual’s chromosome count is 47, rather than 46. In ~95% of cases, the chromosomal abnormality is trisomy of chromosome 21 due to meiotic non-disjunction (i.e. Intellectual disability becomes evident in early childhood as the failure to reach developmental milestones in an expected timeframe. In the postnatal period, characteristic phenotypical features point to the diagnosis: Translocation Down syndrome gene carriersĭiagnosis is often made antenatally and this must occur in conjunction with genetic counseling, which should begin prior to the testing. Increased incidence with increasing maternal age ![]() ![]() The individual risk is strongly dependent on maternal risk, and therefore incidence varies with regional and temporal variation in maternal age distribution and the implementation of antenatal screening. The approximate worldwide incidence is approximately 1 in 800 live births 15. ![]()
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