A Novel GNAS Mutation in a Patient with Ia Pseudohypoparathyroidism (iPPSD2) Phenotype.

Pseudohypoparathyroidism (PHP) is a heterogeneous orphan disease characterized by multihormonal resistance and several phenotypic features. In some cases, PHP is caused by a mutation in the GNAS that encodes the alpha subunit of the G protein, one of the key transmitters of intracellular signals. A correlation between the genotype and phenotype of patients with GNAS mutations has not yet been described. This often makes diagnosis, drug prescription, and timely diagnosis difficult. Information about GNAS functioning and the impact of specific mutations on the clinical course of the disease is limited. Establishing of the pathogenicity by newly identified GNAS mutations will expand the understanding of this gene functioning in the cAMP signaling pathway and may become the basis for personalized treatment. This paper provides a clinical description of a patient with the Ia PHP phenotype caused by a previously unknown mutation in GNAS (NC_000020.11(NM_000516.7)): c.719-29_719-13delinsACCAAAGAGAGCAAAGCCAAG in the heterozygous state. Verification of the pathogenicity of the detected mutation is also described.