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Biomedical subjects

E Thibaud

Publications and source records attributed to E Thibaud.

16 recordsLinked to original sources

XY sex reversal associated with a deletion 5' to the SRY "HMG box" in the testis-determining region.

The human testis-determining factor resides within a 35-kilobase (kb) region of the Y chromosome immediately adjacent to the pseudoautosomal boundary. A candidate gene for human sex determination (SRY) was isolated in this region. Here, we describe a study of 25 cases of XY females with pure gonadal dysgenesis for mutations on the Y chromosome short arm, including SRY. Southern blotting revealed a sex-reversed female harboring a deletion extending from approximately 8 kb from the pseudoautosomal boundary of the Y chromosome to at least 33 kb and no more than 60 kb upstream, toward the centromere. The deletion begins no more than 1.8 kb upstream from the first ATG of the SRY open reading frame present in the clone pY53.3. To our knowledge, no mutation has been described previously outside the SRY "HMG box" on the short arm of the Y chromosome, which is associated with sex reversal. Since the 5' extent of the SRY transcriptional unit has not been defined, the deletion may remove upstream exons of SRY and/or transcriptional regulatory motifs, either situation resulting in lack of testicular development. It cannot be formally excluded that the mutation removes a second locus, independent of SRY, that is critical for sex determination. Denaturant gradient gel electrophoresis analysis of the SRY open reading frame in the remaining 24 cases revealed de novo single base-pair transitions in the SRY conserved domain in 4 cases.

Amino Acid Sequence

Preservation of ovarian function by ovarian transposition performed before pelvic irradiation during childhood.

Ovarian transposition in adults has been shown to protect ovarian function in about 60% of cases by reducing ovarian exposure to less than 4 to 7 Gy. We therefore evaluated the effect of ovarian transposition during childhood or adolescence. Eighteen girls had ovarian transposition performed at a mean (+/- SEM) age of 9.4 +/- 1.2 years (range, 1.2 to 16 years). Twelve were prepubertal and six had menstruated at the time of ovarian transposition. The initial abnormalities were Hodgkin disease (5 cases), iliac Ewing sarcoma (3), medulloblastoma (2), ovarian seminoma (1), and vaginal or uterine tumor (7). The irradiation was external in 11 cases and local by vaginal curietherapy in 7 cases. Fifteen girls received chemotherapy. The ovarian transposition was bilateral in 15 patients and unilateral in 3 cases; in the latter the other ovary had been destroyed by the tumor or by abdominal irradiation. Ovaries were placed just below the iliac crest (15 cases) or posterolateral to the uterus (3); thus, the calculated ovarian radiation dose was up to 9.5 Gy. At the time of evaluation (8.6 +/- 0.9 years after ovarian transposition), 16 girls had menstruated and 2 remained amenorrheic because of major lesions of the vagina and uterus caused by the vaginal curietherapy. Basal plasma gonadotropin values were normal. Ovulation was documented in seven cases. Two pregnancies occurred. Complications of ovarian transposition were present in four patients: intestinal occlusion, dyspareunia, functional ovarian cysts, and pelvic adhesions with tubal obstruction. We conclude that ovarian transposition, performed before abdominopelvic irradiation during childhood, can preserve ovarian function. Longer follow-up is required to assess the risk of ovarian dystrophy because of vascular lesions or chemotherapy.

Adolescent

[Gonadal function after cancer treatments in childhood].

Treatments given for childhood malignancies can alter gonadal function by several mechanisms: (1) cranial irradiation may cause either gonadotrophin deficiency or premature puberty. (2) Irradiation of the testes can induce germinal epithelium dysfunction even if the dose delivered is very low; Leydig cell failure occurs beyond 5-6 Gy and ovarian insufficiency beyond 6-7 Gy. (3) Chemotherapy is considerably more toxic for the germinal epithelium of the testes than for the ovaries; alkylating agents are especially toxic. Analysis of the consequences of preparation for bone marrow transplantation by chemotherapy or total body irradiation will be required when longer follow-up are available.

Antineoplastic Agents

[Role of pelvic ultrasonography in the diagnosis, therapeutic indications and surveillance of central precocious puberty].

The use of pelvic ultrasonography was evaluated as a diagnostic and follow-up tool in girls with precocious puberty. Before treatment 23 of 33 patients with central precocious puberty presented an increased size of the uterus. In 10 cases with prepubertal size of the uterus, the precocious puberty was only beginning or of mild severity. During treatment with a LHRH analogue, changes in uterine size were slow in spite of a satisfactory and rapid control of estrogen secretion. At onset of treatment, transient ovarian cysts were seen in 2 patients. In our experience, pelvic ultrasonography did not provide significant information on the control of the disease by LHRH analogue therapy. Of 16 girls with presumed premature thelarche, 3 presented signs of estrogenic stimulation of the uterus. It remains a useful technique to rule out the presence of ovarian cysts or tumors at time of diagnosis.

Buserelin

[Chemotherapy and ovarian function. Retrospective analysis in 17 girls treated for malignant tumor or hematologic disease].

Ovarian function was investigated in 17 patients aged 13 5/12 to 30 years who had received various types of combined chemotherapy without any irradiation. Ovarian insufficiency was found in 6 cases with amenorrhea (n = 5) or irregular menstruations (n = 1). There is a high risk of sterility in these cases although as described in one case, a normal pregnancy occurred in spite of evidence of ovarian failure. Cyclophosphamide seemed to be less harmful when given before puberty. Great variations in individual susceptibility for relatively low doses were observed with this drug. The combination with other drugs in some protocols might play a role in these cases. At variance with results reported in adults, the MOPP chemotherapy used in children with Hodgkin's disease did not induce ovarian dysfunction.

Adolescent

Long-term results of GnRH analogue (Buserelin) treatment in girls with central precocious puberty.

The GnRH analogue Buserelin was given for one year to six girls with central precocious puberty in a daily subcutaneous dose of 20 micrograms/kg/day. A decrease of plasma estradiol and vaginal maturation index to prepubertal values was obtained in 5 out of 6 cases. Bone maturation decreased and final predicted adult height improved significantly. This analogue of GnRH appears to be an effective medication for gonadotropin dependent precocious puberty in girls.

Buserelin

[True precocious puberty in non-tumor hydrocephalus. An analysis of 16 cases].

True precocious puberty occurred in 16 children (15 girls and 1 boy) with non tumoral shunted hydrocephalus at a mean age of 6.8 years. They had mild clinical manifestations of precocious puberty, and the other pituitary functions were found to be normal. Except for one child, precocious puberty did not correlate with raised intracranial pressure or lack of cerebral drainage by the shunt. Growth was the main concern in this group as the predicted height fell at a mean value of 1.7 SD below the parental target height, and even more in children with myelomeningocele. This growth retardation is due to an early progression of bone age observed even prior to the appearance of breast or pubic hair. Therefore we suggest that these children might benefit from early treatment by an LHRH analogue as soon as precocious puberty occurs.

Age Factors