Isochromosome for the short arm of X: a human mosaic 45,x/46,XXpi.

An 18 year female patient with short stature, amenorrhoea and poorly developed secondary sexual characteristics, has subnormal oestrogen excretion and increased levels of plasma gonadotrophin. Laparoscopy revealed streak ovaries. A reduced number of buccal mucosal cells showed positive sex chromatin. Chromosome studies of blood lymphocytes indicated mosaicism: the major cell line was characterized by an isochromosome for the X short arm, 46,XXpi; the minor cell line had a single X chromosome, 45,X.