A novel GNAS-Gsα splice donor site variant in a girl with pseudohypoparathyroidism type 1A and her mother with pseudopseudohypoparathyroidism

• Published in: Clinical Pediatric Endocrinology Vol. 33; no. 2; pp. 66 - 70
• Main Authors: Sano, Shinichiro, Iwamoto, Shotaro, Matsushita, Rie, Masunaga, Yohei, Fujisawa, Yasuko, Ogata, Tsutomu
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Society for Pediatric Endocrinology 2024
• Subjects: Case Report; GNAS-Gsα; nonsense-mediated mRNA decay; pseudohypoparathyroidism; splice donor site mutation; pseudohypoparathyroidism; GNAS-Gsα; nonsense-mediated mRNA decay; splice donor site mutation
• ISSN: 0918-5739; 1347-7358
• DOI: 10.1297/cpe.2023-0065

We encountered a Chinese girl with pseudohypoparathyroidism type 1A (PHP1A) and her mother with pseudopseudohypoparathyroidism (PPHP). Sequencing analysis of GNAS-Gsα revealed a heterozygous c.212+2T>C variant (NM_000516.4) affecting the canonical splice donor site of intron 2 in the girl and her mother. RT-PCR performed on mRNA samples obtained from cycloheximide-treated and cycloheximide-untreated lymphoblastoid cell lines of this girl revealed the utilization of an alternative splice donor site at 33–34 bp from the boundary between exon 2 and intron 2 and the production of an aberrant mRNA with a retention of a 32 bp intronic sequence between exon 2 and exon 3 (p.(Gly72Lysfs*39)), which satisfied the condition for the occurrence of nonsense-mediated mRNA decay, as predicted by SpliceAI. This study revealed the molecular consequences of disruption of the canonical splice donor site and confirmed the clinical utility of SpliceAI.