The importance of surgical evaluation of patients with "Turner-like" sex chromosomal abnormalities

Risk of malignancy in bilateral streak gonads: the role of the Y chromosome

Although girls with Turner's syndrome (45,X) are not at risk for malignancy, patients with feminizing testicular syndrome with XY chromosome composition and patients with "mixed gonadal dysgenesis" are at risk for malignancy, and bilateral gonadectomy is performed. We have treated seven girls with "Turner-like" syndrome, who we believe are also "at risk" for development of malignancy and in whom gonadectomy should be performed. We present seven cases of phenotypically typical females, without sexual ambiguity, who presented with primary amenorrhea and short stature (5) and/or minor dysmorphic features (2). Chromosome analysis showed 45,X karyotype plus a fragment that we could not rule out as being part of a Y chromosome (in one patient a complete Y chromosome). In two patients, the fragment was subsequently positively identified as a Y, using a DNA probe. In view of the known high incidence of development of gonadoblastoma in the dysgenetic gonads of phenotypic females with a Y chromosome, bilateral gonadectomy was performed in these girls. Bilateral genital streaks with normal uterus and Fallopian tubes were found in all patients. In two patients unsuspected gonadoblastoma, without metastases, was found. In five cases, Leydig cells and tubular structures resembling rete testes were found, cells that are associated with Y-chromosomal tissue. We stress the need for complete chromosomal evaluation of phenotypically female patients with primary amenorrhea or features of Turner's syndrome. If a Y chromosome or the possibility of a Y chromosome cannot be excluded, gonadectomy should be performed because of the risk of malignancy.

Genetic aspects of ambiguous genitalia

The unexpected arrival of an infant with ambiguous genitalia is stressful for both physicians and parents. Careful assessment of the external genital structures and the overall infant directs the immediate management. Investigations include evaluation of glucose, electrolytes, chromosomes, and 17-ketosteroids as well as ultrasound and evaluation of the urinary tract as appropriate. The review of family and pregnancy history addresses concerns regarding medications or previously affected infants. The most efficient method of evaluating such an infant is by a team approach, with each team member contributing expertise and one communicating with the family and the family physician. Unnecessary overlap of investigations can be avoided as well as rash decisions as to sex of rearing. Counseling the family provides support during the stressful first days until decisions can be made about information regarding the diagnosis and prognosis of the infant, recurrence risk figures for subsequent pregnancies or other family members, and whether prenatal diagnosis might be appropriate. The family can be helped to move through the ordeal with their child and develop trust in the team members.

Sex chromosome fragment in a phenotypically normal female. Significance of occult Y-related material

The authors report a 15-year-old short, nonvirilized, prepubertal female whose peripheral karyotype revealed a mosaicism in which 62 percent of the cells had a karyotype of 45X, and the other 38 percent had a karyotype of 46X plus a small unidentified marker chromosome. Since the authors were unable to determine from the karyotype whether this marker was derived from an X or a Y chromosome and because of the high risk for neoplasia in abnormal gonads containing Y material, she underwent surgical exploration, with removal of gonadal tissue. Microscopic examination of the streak gonads revealed a mixture of dysgenetic ovarian and testicular type tissues. The presence of testicular-like tubules strongly implied the presence of Y material in the genotype. Review of the literature reveals at least 19 similar cases in which presumed sex chromosomal markers or fragments were found in phenotypically normal females. Because of the risk of gonadal neoplasia in patients with occult Y chromosomal material, gonadectomy is indicated when the origin of the marker chromosome is uncertain.