Spinal Stenosis with Paraparesis in a Korean Boy with Albright's Hereditary Osteodystrophy: Identification of a Novel Nonsense Mutation in the GNAS.

Children with Albright's hereditary osteodystrophy (AHO) suffering from spinal cord compression are rarely reported worldwide. The association of compressive myelopathy with AHO is not still well known. AHO is a rare heterogeneous group of inherited disorders and results from the GNAS mutation. AHO manifests in two different phenotypes, pseudohypoparathyroidism type Ia (PHP-Ia) and pseudopsedohypoparthyroidim (PPHP), which may happen in the same family members. We present the case of a 15-year-old boy with AHO features, who was later diagnosed with PHP-Ia. He suffered from cervical myelopathy with paraparesis due to spinal stenosis. His mother with AHO phenotype was diagnosed with PPHP without spinal stenosis. Genetic analysis revealed a novel heterozygous nonsense mutation within exon 1 of GNAS(c.49A>T; p.Lys17*) in both of them. This is the first clinically, biochemically, and genetically identified child case of spinal stenosis and paraparesis associated with PHP-Ia, having a novel GNAS mutation in Korea.