Akie Nakamura1, Erika Hamaguchi1, Reiko Horikawa1, Yasuyuki Nishimura1, Keiko Matsubara1, Shinichiro Sano1, Keisuke Nagasaki1, Yoichi Matsubara1, Akihiro Umezawa1, Toshihiro Tajima1, Tsutomu Ogata1, Masayo Kagami1, Kohji Okamura1, Maki Fukami1. 1. Departments of Molecular Endocrinology (A.N., K.M., S.S., M.K., M.F.) and Systems BioMedicine (K.O.) and Institute (Y.M.), National Research Institute for Child Health and Development, Tokyo 157-8535, Japan; Division of Endocrinology and Metabolism (R.H.), National Medical Center for Children and Mothers, Tokyo 157-8535, Japan; Department of Internal Medicine (E.H., Y.N.), Japanese Red Cross Kanazawa Hospital, Kanazawa 921-8162, Japan; Division of Pediatrics, Department of Homeostatic Regulation and Development (K.N.), Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan; Department of Reproductive Biology (A.U.), Center for Regenerative Medicine, National Institute for Child Health and Development, Tokyo 157-8535, Japan; Department of Pediatrics (T.T.), Jichi Children's Medical Center Tochigi, Shimotsuke 329-0498, Japan; and Department of Pediatrics (T.O.), Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
Abstract
CONTEXT: Pseudohypoparathyroidism type 1b (PHP-1b) results from methylation defects at the G protein stimulatory α subunit (GNAS) exon A/B-differentially methylated region (DMR). Although microduplications in the GNAS region were recently identified in two PHP-1b patients, genetic information on these patients remained fragmentary. CASE DESCRIPTION: A 20-year-old Japanese male and his mother presented with hypocalcemia and elevated blood levels of intact PTH. The proband had a maternal uncle who was previously diagnosed with PHP-1b. Methylation-specific multiplex ligation-dependent probe amplification, array-based comparative genomic hybridization, pyrosequencing, fluorescence in situ hybridization, and whole-genome sequencing were performed for this family. The proband, mother, and uncle carried maternally derived approximately 133-kb duplication-triplication-duplication rearrangements at 20q13.32 involving NESP55, NESPAS, XLαs, and exon A/B-DMR but not STX16 or the Gsα coding region. These individuals exhibited partial methylation defects of NESP55-, NESPAS-, and XLαs-DMRs, which were ascribable to the increased copy numbers of these regions retaining the maternally derived methylation pattern and loss of methylation of exon A/B-DMR, which was inexplicable by the copy-number alterations. Fusion junctions of the rearrangement resided within non-repeat sequences and were accompanied by short-templated insertions. CONCLUSIONS: Our results indicate that maternally derived copy-number gains in the GNAS region mediated by nonhomologous end-joining and/or by break-induced replication can underlie autosomal dominant PHP-1b. These rearrangements likely affect methylation of exon A/B-DMR by disconnecting or disrupting its cis-acting regulator(s). This study provides a novel example of human disorders resulting from functional disturbance in the cis-regulatory machinery of DNA methylation.
CONTEXT: Pseudohypoparathyroidism type 1b (PHP-1b) results from methylation defects at the G protein stimulatory α subunit (GNAS) exon A/B-differentially methylated region (DMR). Although microduplications in the GNAS region were recently identified in two PHP-1b patients, genetic information on these patients remained fragmentary. CASE DESCRIPTION: A 20-year-old Japanese male and his mother presented with hypocalcemia and elevated blood levels of intact PTH. The proband had a maternal uncle who was previously diagnosed with PHP-1b. Methylation-specific multiplex ligation-dependent probe amplification, array-based comparative genomic hybridization, pyrosequencing, fluorescence in situ hybridization, and whole-genome sequencing were performed for this family. The proband, mother, and uncle carried maternally derived approximately 133-kb duplication-triplication-duplication rearrangements at 20q13.32 involving NESP55, NESPAS, XLαs, and exon A/B-DMR but not STX16 or the Gsα coding region. These individuals exhibited partial methylation defects of NESP55-, NESPAS-, and XLαs-DMRs, which were ascribable to the increased copy numbers of these regions retaining the maternally derived methylation pattern and loss of methylation of exon A/B-DMR, which was inexplicable by the copy-number alterations. Fusion junctions of the rearrangement resided within non-repeat sequences and were accompanied by short-templated insertions. CONCLUSIONS: Our results indicate that maternally derived copy-number gains in the GNAS region mediated by nonhomologous end-joining and/or by break-induced replication can underlie autosomal dominant PHP-1b. These rearrangements likely affect methylation of exon A/B-DMR by disconnecting or disrupting its cis-acting regulator(s). This study provides a novel example of human disorders resulting from functional disturbance in the cis-regulatory machinery of DNA methylation.
Authors: Danny E Miller; Patrick Hanna; Miranda Galey; Monica Reyes; Agnès Linglart; Evan E Eichler; Harald Jüppner Journal: J Bone Miner Res Date: 2022-08-03 Impact factor: 6.390
Authors: Giovanna Mantovani; Murat Bastepe; David Monk; Luisa de Sanctis; Susanne Thiele; Alessia Usardi; S Faisal Ahmed; Roberto Bufo; Timothée Choplin; Gianpaolo De Filippo; Guillemette Devernois; Thomas Eggermann; Francesca M Elli; Kathleen Freson; Aurora García Ramirez; Emily L Germain-Lee; Lionel Groussin; Neveen Hamdy; Patrick Hanna; Olaf Hiort; Harald Jüppner; Peter Kamenický; Nina Knight; Marie-Laure Kottler; Elvire Le Norcy; Beatriz Lecumberri; Michael A Levine; Outi Mäkitie; Regina Martin; Gabriel Ángel Martos-Moreno; Masanori Minagawa; Philip Murray; Arrate Pereda; Robert Pignolo; Lars Rejnmark; Rebecca Rodado; Anya Rothenbuhler; Vrinda Saraff; Ashley H Shoemaker; Eileen M Shore; Caroline Silve; Serap Turan; Philip Woods; M Carola Zillikens; Guiomar Perez de Nanclares; Agnès Linglart Journal: Nat Rev Endocrinol Date: 2018-08 Impact factor: 43.330