Neonatal McCune–Albright syndrome with survival beyond two years

McCune–Albright syndrome (MAS) is a rare disease resulting from a somatic, mosaic mutation of GNAS1 encoding the G_sα subunit of the G-protein coupled membrane receptor responsible for multiple hormonal signaling cascades. We present a patient with neonatal MAS who initially presented with neonatal diabetes and concern for congenital cardiac disease, and subsequently was found to have significant ACTH-independent neonatal Cushing syndrome. Her course included multi-system organ involvement, although she initially did not have obvious findings consistent with the MAS classic triad of café-au-lait macules, fibrous dysplasia, or peripheral precocious puberty. After medical and surgical treatment, she remains the only reported survivor of neonatal MAS. This clinical report alerts clinicians to the possibility of this disease in neonates with non-classical endocrine and non-endocrine manifestations of MAS, and demonstrates that this very early presentation is potentially survivable.