X-Linked Mental Retardation and an X-Chromosome Marker

This issue of the Journal contains an article by Turner and her colleagues that presents yet another chapter in the rapidly expanding saga of the relation between mental retardation and a cytogenetically detectable change in the X chromosome.

Abstract

This issue of the Journal contains an article by Turner and her colleagues that presents yet another chapter in the rapidly expanding saga of the relation between mental retardation and a cytogenetically detectable change in the X chromosome. The story begins with Penrose's report in 1938 of an excess of males among persons who are institutionalized because of mental retardation.1 The excess has been repeatedly confirmed since then and has been shown to be quite large: there are often 30 to 50 per cent more men than women. In 1974, Gillian Turner and her husband examined the records of all . . .