Endocrine Abstracts

Introduction

Turner syndrome(TS) is characterized by complete/partial monosomy or by a structural defect in one of X chromosomes. Despite clinical hallmarks of short stature(SS) and gonadal dysgenesis(GD), phenotype is variable and related to underlying chromosomal pattern. Loss of the distal segment of the short arm of x-chromosome(Xp-), including haploinsufficiency of short stature homeobox-containing (SHOX) gene, is thought to be the main factor for growth failure. Regarding GD, results from accelerated follicular atresia. Spontaneous puberty occurs in only 15–30%, but only half of those complete puberty with menarche. We report an uncommon presentation of a teenage TS female with normal stature, whose only apparent Turner feature was secondary amenorrhea(SA).

Case report

A 17-year-old girl was referred to our endocrine clinic for SA. Spontaneous menarche occurred at 13 years-old. Subsequent menstruation was regular during first 3 months, and became irregular, in the following 2.5 years. Thereafter, she became amenorrheic during 1.5 years. She was born at term, after an uneventful pregnancy. Her birth length and weight were 50.5 cm (0.48 SDS) and 3300 g (-0.2 SDS). She has mild intellectual disability. Height growth was on P50–75 until 12, with an increase to P90 since then. Her target height is 162.5 cm (-0.11 SDS). Physical examination, recorded 170 cm of height (1.09 SDS; P85), weighed 66 kg (SDS 0.95) and had low set ears. Her breast development and pubic hair were Tanner’s stage III and IV, respectively. Endocrine evaluation revealed FSH levels of 106 UI/l and LH levels of 51.9 UI/l, and undetectable estradiol. The remaining pituitary hormones were within normal ranges, as haematological and biochemical tests. Anti-mullerian hormone was <0.01 µg/l. Pelvic ultrasound revealed an uterus of normal dimensions and ovaries were undetectable. Echocardiogram, audiogram and renal ultrasound were normal. Karyotype analysis showed a 46, X, psu idic(X)(q21.32) TS, representing partial monosomy of Xq and partial trisomy of Xp(long arm of x-chromosome). Low-dose oral contraceptive pill was initiated. Currently, at 20 years-old, she presents a complete pubertal development with a final height of 172 cm (1.34 SDS).

Conclusions

In this case, the SHOX gene overdose in Xp- may have mitigated the SS phenotype which is typical of TS. Additionally, TS karyotype may be a predictor of spontaneous puberty, being less frequent in the classic 45, X karyotype. TS should be considered in patients with SA despite no typical somatic stigmata. There is paucity of literature reporting TS with normal/tall height and spontaneous puberty.