Endocrine Abstracts

Introduction

Noonan syndrome can result from different mutations, the most frequent being in PTPN11. The diagnosis is often made by the clinical picture of short stature, facial dysmorphisms and heart defects. From an endocrine point of view, growth retardation, hypogonadism and a higher frequency of thyroid autoimmunity are highlighted.

Objectives

To analyse endocrine features in patients with Noonan syndrome (SN).

Material and Methods

Review of the clinical files of patients with NS followed in an external endocrinology appointment since 1997.

Results

Data from 4 male patients with NS were analysed. D1: Clinical diagnosis in the 1st year of life and molecular confirmation at age 9 (PTPN11 mutation). Height-weight evolution below P5. Pubertal induction at age 14, with normal gonadal function after testosterone suspension. Currently 26 years old, 1.44m - below the target family height (TFH) of 1.69m - BMI 18.5 kg/m² and dyslipidaemia. D2: Early clinical diagnosis due to dysmorphisms and cardiac anomalies with posterior molecular confirmation (PTPN11 mutation). He presented normal growth rate, hypogonadism with puberty induced at 13 years and 5 months of age and subclinical hypothyroidism with negative autoimmunity. Currently the patient is 35 years old, has 1.74m (within the TFH - 1.75m), BMI 19.9 kg/m² and maintains testosterone therapy. D3: Clinical diagnosis in the postnatal period due to poor height-weight evolution and phenotype, molecular confirmation at age 14 (mutation in SOS1 - Noonan-Querubinism variant). Growth within P5, spontaneous puberty and no hypogonadism. Currently the patient is 23 years-old, 1.65m (TFH 1.79m), BMI 20.6 kg/m², without other endocrine anomalies. D4: Molecular diagnosis at age 14 (PTPN11 mutation). Growth curve at P25–50 and pubertal induction at age 16. Currently 22 years old, 1.73m (within the TFH - 1.70m), BMI of 20.0kg/m², maintains testosterone therapy. All the patients presented heart disease, bone malformations and delayed psycho-motor development. Ophthalmological and dental abnormalities were reported in 3 and haematological anomalies in 1 patient.

Conclusions

In this sample, the endocrine features were heterogeneous: 2 patients reached a stature below the TFH, 1 had short final stature; in all but one, there was a need for pubertal induction; 2 were diagnosed with hypogonadism. Follow-up in appointments allowed for growth monitoring, pubertal induction at the appropriate time, and continued testosterone therapy when indicated.