Le I-Turner syndrome (kwesinye isikhathi kubizwa i-gonadal dysgenesis) Kuyinto isifo sofuzo okuthinta abesifazane kuphela. Lokhu okungavamile kuthinta enye ye-X chromosomes (ama-chromosome ocansi). I-Turner syndrome ithinta cishe 1 kwabesifazane abangu-2 futhi kuvame ukutholakala eminyakeni eminingana ngemva kokuzalwa, ngesikhathi sokuthomba. Izimpawu ezinkulu wubude obufushane kanye nokusebenza okungejwayelekile kwama-ovari. I-Turner syndrome iqanjwe ngodokotela waseMelika owayithola ngo-1938, uHenri Turner.

Amadoda anama-chromosome angu-46 okuhlanganisa namabili okuthiwa ama-chromosome ocansi abizwa ngokuthi i-XY. Ifomula yofuzo yendoda ingama-46 XY. Abesifazane futhi banama-chromosome angu-46 kuhlanganise nama-chromosome ocansi amabili abizwa ngokuthi 46 XX. Ngakho-ke i-genetic formula yowesifazane ingama-46 XX. Kwabesifazane abane-Turner syndrome, inhlanganisela yofuzo iqukethe i-chromosome eyodwa ye-X, ngakho ifomula yofuzo yowesifazane one-Turner syndrome ingu-45 X0. Kuphakathi kokuthi laba besifazane bashoda nge-chromosome engu-X noma i-X chromosome ikhona, kodwa inokungajwayelekile okubizwa ngokuthi ukususwa. Ngakho-ke kuhlale kunokuntuleka kwe-chromosomal.