Gonadal Dysgenesis in a Newborn With XO Karyotype

Abstract

Few reports of karyotype-verified Turner's syndrome in neonates are available. This report is the third such case in which normal primordial follicles were not present in the ovary at the time of birth. In contrast, germ cells have been identified in all except one neonate with XO Turner's syndrome. These findings and the published data in XO embryos support the concept that developmental arrest at the stage of primordial follicle formation and subsequent regression of germinal structures is the most likely morphological basis for the ovarian dysgenesis which accompanies the XO state.Adult women with Turner's syn-. drome (XO karyotype) typically have rudimentary dysgenetic or "streak ovaries" composed of fibrous stroma and lacking germ cells and follicles. Thus, Jones et al1 have sug¬ gested that two X chromosomes are required for normal germ cell popu¬ lation of the developing ovarian cor¬ tex. However, reports of germ cells or primordial follicles, or both in the ovaries of aborted XO fetuses'2 and newborn infants1'' indicate that de¬ velopmental arrest and subsequent regressive changes may combine to produce the "streak ovary" found at a later age. Because reported au¬ topsy studies of infants with Turner's syndrome are few, the nature of the ovarian dysgenesis has not yet been fully clarified. The subject of the present report is a full-term in¬ fant with an XO karyotype and clini¬ cal and autopsy findings typical of Turner's syndrome. Report of a CaseThe patient was the product of a fullterm uneventful pregnancy and delivery in a healthy 19-year-old prima gravida mother. Birth weight was 2,800 gm (16 lb 2)h oz). Physical findings suggestive of Turner's syndrome were noted at birth; these included bilateral pterygium colli, edema of the hands and feet, hypoplasia of the nailbeds, and hypertelorism of the nipples.The infant was well until 19 days of age when sudden development of wheezing, peripheral cyanosis, and signs interpreted as cardiogenic shock precipitated the ter¬ minal hospitalization. Treatment with ox¬ ygen, diuretics, and digitalis were unsuc¬ cessful, and the patient died six hours af¬ ter admission. The karyotype was obtained by post¬ mortem culture of skin fibroblasts. Chromosomes were counted in 51 cells; 3 cells contained 44 chromosomes, 47 cells contained 45 chromosomes, and 1 cell con¬ tained 46 chromosomes. Karyotype of 3 cells with 45 chromosomes revealed ab¬ sence of one X chromosome in each. The sex chromatin body was absent in the buccal smear obtained postmortem. Autopsy SummaryThe infant was a well nourished phenotypic girl, 49 cm (1 ft IVt in) in crown-heel length with a head cir¬ cumference of 34 cm. The face was unusually triangular with a broad brow and slight hypognathism. Ocu¬ lar hypertelorism was absent, but there were prominent bilateral epi¬ canthic folds. The arch of the palate was intact but high; symmetrical webbing of the neck was prominent, but no subcutaneous masses (lymphangiomata) were palpable. The configuration of the thorax was nor¬ mal. Hypertelorism of the nip...

Additional evidence of gradual loss of germ cells in the pathogenesis of streak ovaries in Turner's syndrome.

“…Hodel and Egli (1965) found no germ cells in the ovary of the 45,X infant they examined. In a recent report, Bove (1970) found germ cells and germinal nests simulating primordial follicles but no normal follicles. The high incidence of infants who have a 45,X karyotype and who also have germ cells and primordial follicles is in contrast to the rarity of these findings in adolescent and adult patients with the same karyotype.…”

Turner’s Syndrome – Review of the Literature with Reference to a Successful Pregnancy Outcome

“…Gonads in 45,XO fetuses are normal up to the third month of gestation, and they have germ cells [2]. In these infants, the gonads have clusters of germ cells or even primordial follicles [3]. The loss or deletion of an X chromosome usually causes rapid atre sia of germ cells, so that at the time of birth, or soon afterwards, only nonfunctioning streak gonads remain.…”

Cytogenetic and Clinical Study on 100 Cases of Primary Amenorrhoea

“…In the first trimester of pregnancy, normal amounts of primordial germ cells have been found in the gonads of 45,X foetuses but in the later stages of pregnancy their amount is smaller than in foetuses of corresponding gestational age with 46,XX chromosome constitution (Singh and Carr 1966, Rushton et al 1969). Minor amounts of primary follicles have been found in the gonads of some neonates with Turner's syndrome on autopsy (Frdand et al 1963, Conen andGlass 1963), although there are reports also on cases in which the gonads were connective tissue throughout (Court-Brown et al 1964, Bove 1970. On the basis of these studies it can be concluded that the germ cells that have travelled to the gonads of the 45,X individuals are destroyed gradually.…”