Neonatal osteoma cutis due to a mutation in GNAS

: We describe a 4-week-old baby boy who presented with white firm cutaneous nodules and failure to thrive. He did not have dysmorphic features, and laboratory tests including serum calcium, phosphorous, thyroid function, and parathyroid hormone level were within normal ranges. Whole exome sequencing revealed an inactivating mutation in GNAS that was previously described as causing pseudohypoparathyroidism.