Endocrine Abstracts

JOINT1911

Neurofibromatosis–Noonan syndrome (NFNS) is a rare genetic entity associated with the clinical phenotype of two conditions: neurofibromatosis type 1 syndrome (NF1) and Noonan syndrome (NS). Sellar and suprasellar disorders with or without pituitary hormone deficiencies are not commonly associated with both NF1 and NS. However, there are reported cases of such presentations in both adults and children with NF1 or NS. To-date, there is only a case of 13-year-old girl with NFNS reported to have isolated growth hormone deficiency with pituitary hypoplasia. We describe the case of an 1-year-old boy with clinical NFNS, anterior pituitary hypoplasia, transient central adrenal insufficiency (CAI) and thyrotropin deficiency (TSHD) presented at 9 months old with failure to thrive (both height and weight < 3rd centile), severe airway obstruction required tracheostomy secondary to right neck plexiform neurofibroma and recurrent hypoglycaemia. The diagnosis of TSHD was established with inappropriate low normal TSH and low FT4. CAI was diagnosed with a hypoglycaemic (glucose 2.9 mmol/l)critical sampling showing an inappropriate low cortisol level of 155 nmol/land an undetectable early morning ACTH levels. He was treated with hydrocortisone and levo-thyroxine replacement at that time. A Synacthen test off hydrocortisone showed normal cortisol response (Peak cortisol 590.6 nmol/l)and normal ACTH of 6.78pmol/lat 11-month-old followed by a normal 16 hours diagnostic fasting test profile. His other pituitary profile revealed normal IGF-1, prolactin and pre-pubertal levels of gonadotropins. The diagnosis of NFNS was made as he fulfilled the diagnostic criteria of NF1 (> 6 café-au-lait spots (>5 mm) with one plexiform neurofibroma) and the Van der Burgt criteria of NS. Clinically, he has short stature, frontal bossing, café-au-lait spots and pectus excavatum. His pituitary MRI findings revealed a small anterior pituitary gland. In summary, we presented a 1-year-old boy with NFNS and anterior pituitary hypoplasia. The case is the youngest NFNS patient to have pituitary hormone deficiencies with abnormal pituitary imaging in the literature. The findings in this patient show that seller or suprasellar anomalies with pituitary hormone deficiency can be a feature of NFNS as early as infancy. Therefore, there should be a high index of suspicion of pituitary hormone deficiency in children with NFNS.