Endocrine Abstracts

Background: Mutations in BRAF are a rare cause of cardiofaciocutaneous syndrome (CFC). Recently, BRAF mutations have been reported in papillary craniopharyngiomas, but have not been described in patients with other hypothalamo-pituitary abnormalities. We describe three patients with CFC and septo-optic dysplasia (SOD) associated with heterozygous BRAF mutations.

Cases: Patients presented in childhood with clinical features of genetically proven CFC, short stature (height <0.4th centile) and MRI features of SOD. In cases 1 and 2, GH deficiency was initially observed (see Table 1), with case 1 subsequently developing gonadotrophin deficiency and a low-normal T₄ and TSH, requiring levothyroxine replacement. Case 2 developed TSH deficiency and case 3 partial ACTH deficiency.

In situ hybridisation performed on human embryonic brain and hypothalamo-pituitary sections showed strong BRAF mRNA transcript expression at Carnegie stages (CS) 19, 20, 23, and 8 post-conception weeks, in the hypothalamus/ventral diencephalon, Rathke’s pouch, trigeminal ganglia, retina, spinal cord, and ganglia.

Conclusion: We report the first novel association of SOD and CFC secondary to BRAF mutations. Endocrine features include GH deficiency, with evolution of other pituitary abnormalities. Patients with CFC should be screened for pituitary defects as these may be associated with morbidity. BRAF therefore appears to be implicated in normal hypothalamo-pituitary function.