Twenty-six years later: a woman with tetra-X chromosomes.

The article presents a discussion on a woman with tetra-X chromosomes, who has maintained good physical health for so long. All this may be partially due to possible mosaicism in the present instance, though without evidence of a normal cell line. Mosaics are reportedly not necessarily less markedly affected, physically or mentally, than females in whom only tetra-X sex chromosomes are apparent. It is notable that intellectual deterioration has not occurred either on the basis of clinical evidence or of formal psychometric testing. Indeed, the latter, using the Wechsler Adult Intelligence Scale, currently showed higher scores than 26 years ago, perhaps due to living in a congenial and attentive private home in contrast to earlier life in a large. inevitably less personal and stimulating. institutional setting.