Medical Genetics - V. M. Zaporozhan 2005

Chromosomal Diseases
History of Human Cytogenetics

Chromosomal Disorders are Hereditary diseases caused by alterations in chromosome number and Structure. The branch of genetics that studies the Structure and function of Chromosomes in various organisms is called cytogenetics. As a science, cytogenetics has been developing since the early 20th century. In 1902, Sutton and Boveri first hypothesized that genes reside on chromosomes. In 1903, Sutton introduced the term «cytogenetics». In 1911, Thomas Morgan formulated the fundamental principles of the chromosomal theory of inheritance.

Almost all major discoveries in PLANT AND ANIMAL cytogenetics were made in the first half of the 20th century. Human cytogenetics began to truly advance only in the 1950s, after Tjio and Levan in 1956 applied a new technique for preparing human chromosome spreads and established that the normal Human Karyotype consists of 46 chromosomes. In 1959, the French cytogeneticist Lejeune discovered trisomy 21 in Down syndrome, while Ford et al. (1959) and Jacobs and Strong (1959) reported the 47,XXY karyotype in Klinefelter syndrome and the 45,X karyotype in Turner syndrome. The causes of Patau and Edwards syndromes were discovered in 1960. In 1963, Lejeune described the first syndrome associated with a chromosomal deletion — the cri-du-chat syndrome. In 1968–1970, chromosome banding techniques were developed, enabling the precise identification of all Selection/39.html">Human chromosomes and the detailed study of Chromosomal aberrations.

Table 5.1. Chromosomal and genomic Mutations in Spontaneous Abortion Materials