TY - JOUR
T1 - High-throughput Molecular Analysis of Pseudohypoparathyroidism 1b Patients Reveals Novel Genetic and Epigenetic Defects
AU - Danzig, Jennifer
AU - Li, Dong
AU - Jan De Beur, Suzanne
AU - Levine, Michael A.
N1 - Funding Information:
This work was supported in part by National Institutes of Health T32 training grant 5T32DK063688, NIH R01 DK56178 (M.A.L.), a Pediatric Endocrine Society Research Fellowship Award, and The Children's Hospital of Philadelphia Research Institute.
Publisher Copyright:
© 2021 The Author(s). Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved.
PY - 2021/11/1
Y1 - 2021/11/1
N2 - Context: Patients with pseudohypoparathyroidism type 1b (PHP1b) show disordered imprinting of the maternal GNAS allele or paternal uniparental disomy (UPD). Genetic deletions in STX16 or in upstream exons of GNAS are present in many familial but not sporadic cases. Objective: Characterization of epigenetic and genetic defects in patients with PHP1b. Design and Patients: DNA from 84 subjects, including 26 subjects with sporadic PHP1b, 27 affected subjects and 17 unaffected and/or obligate gene carriers from 12 PHP1b families, 11 healthy individuals, and 3 subjects with PHP1a was subjected to quantitative pyrosequencing of GNAS differentially methylated regions (DMRs), microarray analysis, and microsatellite haplotype analysis. Setting: Academic medical center. Main Outcome Measurements: Molecular pathology of PHP1b. Results: Healthy subjects, unaffected family members and obligate carriers of paternal PHP1b alleles, and subjects with PHP1a showed normal methylation of all DMRs. All PHP1b subjects showed loss of methylation (LOM) at the exon A/B DMR. Affected members of 9 PHP1b kindreds showed LOM only at the exon A/B DMR, which was associated with a 3-kb deletion of STX16 exons 4 through 6 in 7 families and a novel deletion of STX16 and adjacent NEPEPL1 in 1 family. A novel NESP deletion was found in 1 of 2 other families with more extensive methylation defects. One sporadic PHP1b had UPD of 20q, 2 had 3-kb STX16 deletions, and 5 had apparent epigenetic mosaicism. Conclusions: We found diverse patterns of defective methylation and identified novel or previously known mutations in 9 of 12 PHP1b families.
AB - Context: Patients with pseudohypoparathyroidism type 1b (PHP1b) show disordered imprinting of the maternal GNAS allele or paternal uniparental disomy (UPD). Genetic deletions in STX16 or in upstream exons of GNAS are present in many familial but not sporadic cases. Objective: Characterization of epigenetic and genetic defects in patients with PHP1b. Design and Patients: DNA from 84 subjects, including 26 subjects with sporadic PHP1b, 27 affected subjects and 17 unaffected and/or obligate gene carriers from 12 PHP1b families, 11 healthy individuals, and 3 subjects with PHP1a was subjected to quantitative pyrosequencing of GNAS differentially methylated regions (DMRs), microarray analysis, and microsatellite haplotype analysis. Setting: Academic medical center. Main Outcome Measurements: Molecular pathology of PHP1b. Results: Healthy subjects, unaffected family members and obligate carriers of paternal PHP1b alleles, and subjects with PHP1a showed normal methylation of all DMRs. All PHP1b subjects showed loss of methylation (LOM) at the exon A/B DMR. Affected members of 9 PHP1b kindreds showed LOM only at the exon A/B DMR, which was associated with a 3-kb deletion of STX16 exons 4 through 6 in 7 families and a novel deletion of STX16 and adjacent NEPEPL1 in 1 family. A novel NESP deletion was found in 1 of 2 other families with more extensive methylation defects. One sporadic PHP1b had UPD of 20q, 2 had 3-kb STX16 deletions, and 5 had apparent epigenetic mosaicism. Conclusions: We found diverse patterns of defective methylation and identified novel or previously known mutations in 9 of 12 PHP1b families.
KW - GNAS
KW - epigenetics
KW - imprinting
KW - parathyroid hormone
KW - pseudohypoparathyroidism
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U2 - 10.1210/clinem/dgab460
DO - 10.1210/clinem/dgab460
M3 - Article
C2 - 34157100
AN - SCOPUS:85119508980
SN - 0021-972X
VL - 106
SP - E4603-E4620
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
IS - 11
ER -