Self-Perpetuating Ring Chromosome in a Patient With Gonadal Dysgenesis

An infant with multiple congenital anomalies and a ring chromosome in group C (X-6-12).

“…Unfortunately, in the absence of autoradiographic studies, it was not possible to prove the true identity of the ring chromosome. She possessed a structural variant in group D(13-15) somewhat similar to that found in the patient of Lindsten and Tillinger (1962).…”

“…The formation of XO cells by secondary loss of the ring leads to XO/XXR mosaicism and consequently a significant proportion show features of Turner's syndrome (Bishop et al, 1966). The ovaries were only examined in one patient (Lindsten and Tillinger, 1962) and were found to be hypoplastic with reduced numbers of primordial follicles.…”

“…Ring X chromosomes appear to be equally rare, the only seven patients recorded having an XO/XXR configuration (Lindsten and Tillinger, 1962;Luers, Struck, and Nevinny-Stickel, 1963;Hustinx and Stoelinga, 1964;Pfeiffer and Buchner, 1964;Fisher, 1965;Bain, Gauld, and Farquhar, 1965;Bishop, Blank, Simpson, and Dewhurst, 1966). Most of them showed features of Tumer's syndrome.…”

Two Human X-Autosome Translocations Identified by Autoradiography and Fluorescence

“…In virtually all cases of structurally abnormal X chromosomes, such as rings [36,37], deletions [38,39], and isochromosomes [40][41][42], the abnormal X is invariably the late-replicating element in females heterozygous for such rearrangements. These chromosomal abnormalities all involve the loss of some X-chromosomal material and would constitute a nullisomic condition for the deleted segment if the normal X chromosome were inactivated.…”

Two Pregnancies in a 45, X/46, Xr(X)/46, XX Turner Mosaic Patient

“…The frequen cy of menstruation and fertility is somewhat higher in mosaic Turner's syndrome patients (45,X/46,XX), who constitute ~ 7-10 % of the cases of T urner's syndrome [ 1 ]. Turner's syndrome associated with an X ring chromo some, r(X), has been reported infrequently since Lindsten and Tillinger [2] described the first patient. In mosaic Turner's syndrome, the case of mosaicism of 45,X/ 46,Xr(X)/46,XX is rare and there has been no report on pregnancy in this type of Turner's syndrome.…”