Neuropathology Of Down's Syndrome

Neuropathology Of Down's Syndrome

Down’s syndrome is the most commonly identified cause of mental retardation occurring in 1 out of 700 live births. In addition to mental deficiency, characteristics of the disease include epicanthic folds of the eyes, flattened facial features, unusual palm creases, short stature, open mouth, protruding tongue and poor posture. A twenty-two to fifty fold increase in risk of the development of leukemia along with congenital heart defects in forty percent of these individuals is also seen. The increased level of purines often found can lead to mental retardation itself. Neurological impairment and immune system deficiencies make these individuals more susceptible to infection. Also noted are increased risk for cataract development and vision impairment due to defects in the lenses of the eyes.

Evidence for the disease can be found as far back as the nineteenth century with many theories for the etiology of the disease. Early hypotheses include links to endocrine gland malfunction, tuberculosis, syphilis and "uterine exhaustion". The idea of uterine exhaustion was based on the observation that many children with Downs Syndrome (DS) tended to be the last born members of large families. This was later accounted for as mere coincidence. The first formal reference to the anomaly came in 1866 in England by a physician at the Earlewood Asylum noting the distinct physical characteristics of this group of individuals. In the 1930’s, Adrian Bleyer hypothesized that the condition was caused by a failure of the chromosomes to separate but could provide no proof for this since an accurate human chromosome count had not yet been obtained by anyone. The correct number of 46 chromosomes was obtained in Sw...

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