Background: Turner syndrome is the most common sex chromosome disorder in females and occurs in about 1/2500 newborn girls worldwide. On chromosomal analysis, the various karyotypes observed are: 45,X (50%); 45,X/46,XX (20%); 46,X, i(Xq) (15%); 46,X, r(X) or 46,X, del(X) (10%); and others (5%).
Objective and hypotheses: We present the case of a 17-year-old girl referred to our service for primary amenorrhea. Clinical examination: height=163 cm (62nd percentile), weight=59 kg. Sexual development was: PIII BII. She associates several suggestive clinical aspects for Turner syndrome even if there is no stature deficit.
Method: The result of the Barr test (sexual chromatin) was positive, so an X chromosome monosomy (45,XO) was not confirmed. We continued the genetic investigation with a karyotype analysis, followed by a structural analysis of the X chromosomes, confirming a structural anomaly of the X chromosome: long arm deletion of X chromosome (46,X, del (X) (q13-qter)). Primary amenorrhea associated with a hormonal profile of hypogonadotropic hypogonadism is suggestive for a gonadal dysgenesis. Pelvis ultrasonography revealed a hypoplastic uterus, absence of the right ovary and a small left ovary, with three to four follicles. No associated cardiac or renal malformations were revealed.
Results: Under oestro-progestative substitution treatment, menarche, sexual development (PIV BIII), and additional stature gain (5 cm/6 months) were obtained. The hand bone age of 14 years shows an additional growth potential.
Conclusion: No stature deficit (non-mutated SHOX gene) associated with clinical features of Turner syndrome. Rare structural anomaly of the X chromosome: long arm deletion, usually associated with secondary amenorrhea (DAX1 gene responsible for ovaries development being situated on the short arm of the X chromosome). Studies revealed that large Xq deletions proximal to Xq21 led to gonadal digenesis, and half of these patients showed Turner syndrome stigmata. In the literature we find several cases of Xq deletion.
18 Sep 2014 - 20 Sep 2014