Biology

There Major Syndromes Found in Human Being 1. Down Syndrome The cause of this geneticdisorder is the presence of an additional copy of the chromosome number 21 (trisomy of 21). This disorder was first described by LangdonDown (1866). The affected individual is short statured with small round head, furrowedtongue and partially open mouth (Figure 5.16).Palm is broad with characteristic palm crease.Physical, psychomotor and mental development is retarded 2. klinefelter's Syndrome This geneticdisorder is also caused due to the presence of an additional copy of X-chromosome resultinginto a karyotype of 47, XXY. Such anindividual has overall masculine development , however, the feminine development (development of breast, i.e., Gynaecomastia)is also expressed (Figure 5.17 a). Suchindividuals are sterile 3. Turner's Syndrome Such a disorder iscaused due to the absence of one of the X chromosomes, i.e., 45 with X0, Such femalesare sterile as ovaries are rudimentary besid...