Online Education Kit: 1950's

1959: Chromosome Abnormalities Identified

Image of 3 copies of chromosome 21

Professor Jerome Lejeune and his colleagues discovered that Down syndrome, first classified by J. L. H. Down in 1866, is caused by trisomy 21 - that is, having three instead of 2 copies of chromosome 21. The extra copies of the genes on chromosome 21 affect the development of the brain and body.

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References:

Lejeune, J., Gautier, M., Turpin, R. Etude des chromosomes somatiques de neuf enfants mongoliens. C R Acad Sci, 248: 1721-1722. 1959. [PubMed]

Ford, C.E., Miller O.J., Polani P.E., de Almeida, J.C., Briggs, J.H. A sex-chromosome anomaly in a case of gonadal dysgenesis (Turner's syndrome). Lancet, 1: 711-713. 1959. [PubMed]

Jacobs, P.A., Strong, J.A.. A case of human intersexuality having a possible XXY sex-determining mechanism. Nature, 183: 302-3.1959. [PubMed]

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Last Reviewd: April 23, 2013