ICEECE2012 Poster Presentations Calcium & Vitamin D metabolism (73 abstracts)
1National Hospital Organization Kyoto Medical Center, Kyoto, Japan; 2National Hospital Organaization Nagoya Medical Center, Nagoya, Japan; 3National Hospital Organization Kumamoto Medical Center, Kumamoto, Japan; 4National Hospital Organization Kagawa Childrens Hospital, Zentsuji, Japan; 5Hokkaido P.W.F.A.C Sapporo-Kosei Kyosai Clinic, Sapporo, Japan; 6Toyota Memorial Hospital, Toyota, Japan.
Objective: Pseudohypoparathyroidism type 1b (PHP-1b) is rare disorders resulting from genetic and epigenetic aberrations in the GNAS locus. PHP-1b usually defined by isolated renal resistance to PTH, is due to a maternal loss of GNAS exonA/B methylation, leading to decreased Gsα expression in specific tissues. To clarify the usefulness of methylation specific multiplex ligation-dependent probe amplification (MS-MLPA), we evaluate the genetic and epigenetic changes of GNAS comlex in PHP1b patients.
Patients and measurements: We studied a total of 13 subjects with PHP-1b (three families with nine affected members and four sporadic cases). The methylation status of GNAS DMRs was then evaluated using MS-MLPA. The presence of deletion mutation in GNAS complex and STX16 were assessed by using MLPA.
Results: In all the familial PHP1b cases, 3 kb deletion of STX16 and de-methylation of A/B domain were identified. In contrast, no deletion had been detected thoughout GNAS regions, however, methylation abnormalities were widely observed in the GNAS DMRs.
Conclusions: MS-MLPA facilitates precise and rapid analysis of methylation status in GNAS DMRs as well as detection of micro deletion mutation in PHP-Ib. MS-MLPA assays is useful molecular tools for understanding the molecular bases and confirming the diagnosis of PHP-1b.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.