Y chromosome mosaicism in turner syndrome patients

Abstract

Chromosome anomalies accompanying Turner syndrome were found in lymphocyte culture of 230 patients . Chromosomal analysis revealed karyotype 45,X in 117 (50,9%) patients, X monosomy mosaics or structural rearrangements of X chromosome was established in 104 (45,2%) patients . In 9 (3,9%) patients with typical features of Ulrich-Turner syndrome a Y chromosome was found . In 7 mosaics 45,X/46,XY the proportion of XY clone ranged from 46% to 76% . In one of these patients the Y chromosome was dicentric . In most cases of 45,X/46,XY mosaicism, the cause is considered to be the loss of the Y chromosome because of nondisjunction after normal disomic fertilization . In one patient there was apparent nondisjunction of a primary 46,XY conceptus resulting in mosaicism 45,X/46,XY/47,XYY (in 43%, 47% and 10% of cells respectively) . In one patient only 47,XYY cells were found (only blood culture investigated) . The youngest patient was a newborn baby (mixed gonadal dysgenesis was suspected only for this patient), the oldest was 50 years old . The age of most patients ranged between 15 and 23 years . Mental development of patients was corresponding to their age.