Endocrine Abstracts

Introduction: Noonan syndrome is a genetic disorder that usually occurs on a sporadic basis (de novo mutuations) or with autosomal dominant inheritance. Patients present with dysmorphic facial features, cardiac disorders and short stature. Delay of puberty can also be noted. We present here an adult case of Noonan syndrome.

Presentation: A 25 years old male presented to our department with low stature, decreased libido and absence of any secondary sexual characteristic. Fifteen years ago, he was diagnosed with Noonan syndrome, but had no further management, because he was lost in follow up. On clinical examination his height was 156 cm and his weight 44 kg (BMI:18 kg/m²). He had the distinctive facial features of the syndrome (triangle-shaped head, wide forehead, hypertelorism, and low-set posteriorly rotated ears), bilateral cryptorchidism, hypoplastic scrotumn, pennis length 5.5 cm, pubic hair Tanner stage II, and absence of facial hair. Laboratory evaluation revealed: testo:0.025 ng/ml, LH: 8.55 mIU/ml, FSH: 40.31 mIU/ml and normal IGF1 for his age (439 ng/ml). His bone age was delayed (12–13 years old), and had osteoporosis of the lumbar spine (T score: −3.1). Testosterone replacement therapy was initiated in order to promote the development of secondary sexual characteristics and the improvement of his muscle mass, bone density and libido.

Conclusions: In patients with Noonan syndrome delayed puberty should be treated in females after the age of 13 with estradiol or conjugated estrogens, and in males after the age of 14 with testosterone, as early as possible. Treatment with GH is also indicated, especially in patients with certain genetic mutations, starting at the prepubertal period to help patients to achieve an adult height and to promote bone growth.