FULL BLOWN HYPERFUNCTIONING ENDOCRINOPATHIES IN MCCUNE ALBRIGHT SYNDROME: CHALLENGES IN MANAGEMENT

Abstract

INTRODUCTIONMcCune Albright syndrome is a rare, wide spectrum of disease caused by post zygomatic GNAS mutation leading to activation of functions. It is characterized by typical skin hyperpigmentation and distribution, skeletal dysplasia and hyperfunctioning endocrinopathies. RESULTSNS, a 6-year-old Malay girl, presented at 5 months old with PV bleed. She was referred to us at 13 months old. She has extensive hyperpigmented lesions following line of Blaschko on nape, trunk and limbs with rickets changes. LH:0.1 mU/L, FSH:0.1 mU/L, Estradiol: 190 pmol/L. ALP:768 IU/L, Ca:2.68 mmol/L, PO4:1.28 mmol/L, TRP:86%, Mg:0.9 mmol/L, Vitamin D: 68 nmol/L. NS was started on oral cholecalciferol, calcitriol and Sandoz phosphate. At 3 years old, she was symptomatic for hyperthyroidism, TSH:<0.02, fT4:33 pmol/L needing carbimazole. Subsequently she continues to develop multiple long bone fractures associated with trivial falls. Intravenous Pamidronate was started for worsening bone pain. At 4 years 6 months, her PV bleed recurred every 2-3 monthly. LH: <0.2 mU/L, FSH: <0.2 mU/L, Estradiol:107 pmol/L. Pelvic ultrasound – showed bilateral ovarian follicular cyst . Bone age was advanced. Unfortunately she was unable to tolerate aromatase inhibitor (Letrozole). Simultaneously, she has height acceleration with frontal bossing. IGF-1: 168-249 ug/L (22-200), random GH: 4-12 ug/L (0.077-5.00). Her prolonged OGTT was not supressed. MRI brain and pituitary was normal. Long acting octreotide was started for GH excess. NS is currently under close surveillance of her endocrinopathies which has affected her mobility making her- dependent on parents for ADL. Otherwise she is asymptomatic. CONCLUSIONThis case illustrates the severe spectrum of McCune Albright syndrome. NS manifested with full blown hyperfunctioning endocrinopathies which proved to be challenging in management. She has gonadotropinindependent estrogen production, hyperthyroidism and GH excess. Her FGF-23 induced renal phosphate wasting is an important evidence of her fracture risk and complications.