ESPE Abstracts

Background: Prader–Willi syndrome (PWS) is a rare genetic disorder caused by a loss of function of specific genes on chromosome 15. It is characterized by infantile lethargy and hypotonia causing poor feeding and failure to thrive, childhood obesity, short stature, and hypogonadism, that causes incomplete, delayed, and sometimes disordered pubertal development.¹ Precocious puberty is very rare in PWS. We report a girl with PWS and idiopathic precocious puberty treated with gonadotropin-releasing hormone analogue.

Clinical Case: Our patient was born at 35 weeks of gestation weighing 1370 g and displayed poor feeding, poor weight gain and hypotonia during the neonatal period. She was held in neonatal intensive care unit; genetic investigations disclosed maternal uniparental disomy of chromosome 15, responsible for 30% of cases of PWS. After the diagnosis, the patient was referred to our hospital to continue the follow-up. At 7 years and 10 months of age, the physical examination revealed bilateral thelarche and pubarche (Tanner stage: Breast 2, Axilla Hair 1, Pubic Hair 2). At this assessment the auxological parameters were: height 1.12 SDS, weight 1.90 SDS and BMI 1.87 SDS. In the suspicious of central precocious puberty (CPP), GnRH test was performed, showing both an increase in luteotropic hormone (LH) peak (39.4 mIU/ml) and a reversal of LH/FSH ratio compatible with activation of the hypothalamus pituitary gonadal axis (results are summarized in Table1). Pelvic ultrasonography showed uterus of size and morphology compatible with initial puberty. The main causes of peripheral precocious puberty have been ruled out.

So, GnRH analogue therapy was started (triptorelin at the dose of 3.75 mg every 3 months), obtaining a good clinical and hormonal response. However, after 1 year and 5 months, treatment was interrupted due to an excessive deceleration of statural growth and increase of BMI.

Conclusion: There is a very limited amount of information in the literature concerning association of precocious puberty with PWS. Cases of CPP in both patients with uniparental disomy and chromosome 15 deletion have been reported in the literature². Currently, the existence of a correlation between the occurrence of CPP and the type of genetic abnormality responsible for PWS has not yet been studied. Other studies are necessary to understand the pathophysiology implicated in timing of pubertal onset in this syndrome.