ESPE Abstracts

Background: The stimulatory G-protein α-subunit encoded by GNAS exons 1–13 (GNAS-Gsα) mediates signal transductions of multiple G-protein-coupled receptors including arginine vasopressin (AVP) receptor 2 (AVPR2). To date, various germline-derived loss-of-function variants of maternal and paternal origin have been found in pseudohypoparathyroidism type Ia and pseudopseudohypoparathyroidism respectively, and specific somatic gain...

Object: IGF2 is a paternally expressed gene involved in the development of Silver-Russell syndrome (SRS). Here, we report six Japanese patients with IGF2 mutations and compare clinical findings between patients with IGF2 mutations including literature cases and those with H19/IGF2:IG-DMR epimutations.Patients: We recruited six Japanese patients with IGF2 mutations. Th...

Loss of methylation (LOM) at GNAS-A/B:TSS-differentially methylated regions (DMRs) in the GNAS locus is observed in pseudohypoparathyroidism type 1B (PHP1B). Many PHP1B cases are sporadic, but autosomal dominant-PHP1B has a deletion involving NESP55 expressed from the maternal allele or STX16 located upstream of the GNAS locus on the maternal allele. We report the possible first familial PHP1B cases with retrotransposon insertion in the GNAS locus on the maternal allele. To ou...

Background: N-acetylneuraminic acid synthetase-congenital disorder of glycosylation (NANS-CDG) is a recently established rare autosomal recessive disease caused by pathogenic variants in NANS involved in the biosynthesis of N-acetylneuraminic acid (the most common member of sialic acids). Sialic acids are ubiquitously distributed in the body including the brain and skeletal system, and are required for the development and function of multiple organs/tissues. C...