In 1866, John Langdon Down realised that there were numerous physiologic similarities between a numbers of children’s with retardation. The identification of the chromosomal anomaly regarding the pair 21 (the cause of this syndrome), it began to use the term trisomy 21, or Down syndrome.
It is the most common and most known for the chromosomal alterations. It results in the existence of 47 chromosomes instead of 46, being the extra element the chromosome
21. In the pattern trisomy 21 the genetic material in excess is on the pair of chromosome 21, and is the result of an anomaly in the cellular division on the time of the fertilization of the egg by the sperm and occurs in 95% of the cases. Approximately 1% of the cases have pattern trisomy 21 meaning that not all the cells have an alteration of the chromosome 21. In these cases the characteristics are less marked and the mental retard is less sever then in the other cases. The rest of the 4% the alteration occurs due to translocation; there is an extraordinary disruption of the chromosome 21, that adheres to another chromosome (in this case is important to make a genetic study of the family).
When can be diagnosed?
The Down syndrome can usually be diagnosed at birth or shortly after, by their phenotypic characteristics:
Hypotonia, brachycephalic head with a flattened occipital lobe, eyes with folds on the corners, nose root low, the language usually large and fissured, small hands and broad, short fingers and misuse of the 5th finger, extended interval between the 1st and 2nd toes, small ears, external genitalia poorly developed, low and average height, in 40% of cases a fetal hearts malformation.
How is the personality of children with Down syndrome?
The intellectual deficiency exists with an IQ of between 25 and 50. The subjects with Down's syndrome have very different personalities, different learning styles, obedience and humour.
When and what can we do to improve their quality of live and self development?
Since a very early age they should be provided with extensive health evaluations, early stimulation, physical therapy, strengthening of reporting and assessment of development.