(i) List the chromosomal disorders a human may suffer from if karyotype analysis of the individual shows 47 chromosomes instead of the normal 46.
(ii) Explain the cause that results in the gain of chromosome number.
(iii) Mention the symptoms of anyone the disorders an individual can suffer from.

(i) Down's syndrome, Edward's syndrome, Patau's syndrome, Klinefelter's syndrome; Superfemale, Supermale.
(ii) All these disorders result due to nondisjunction.
(iii) Klinefelter's Syndrome. Klinefelter's syndrome is due to the trisomy of sex (X) chromosome. It is formed by the union of an abnormal XX egg and a normal Y sperm or normal X egg and abnormal XY sperm. The individual has 47 chromosomes (44+XXY). Such persons are sterile males (called feminized males) with undeveloped testes, mental retardation, females like sparse body hair, knock knees, long limbs, and some female characteristics such as feminine pitched voice and enlarged breasts (gynecomastia). It is considered that the more the X chromosomes, the greater the mental defect.