Genome-wide multilocus imprinting disturbance analysis in Temple syndrome and Kagami-Ogata syndrome

Abstract

Purpose:Recent studies have identified multilocus imprinting disturbances (MLIDs) in a subset of patients with imprinting diseases (IDs) caused by epimutations. We examined MLIDs in patients with Temple syndrome (TS14) and Kagami-Ogata syndrome (KOS14).Methods:We studied four TS14 patients (patients 1–4) and five KOS14 patients (patients 5–9) with epimutations. We performed HumanMethylation450 BeadChip (HM450k) analysis for 43 differentially methylated regions (DMRs) (753 CpG sites) and pyrosequencing for 12 DMRs (62 CpG sites) using leukocyte genomic DNA (Leu-gDNA) of patients 1–9, and performed HM450k analysis for 43 DMRs (a slightly different set of 753 CpG sites) using buccal cell gDNA (Buc-gDNA) of patients 1, 3, and 4. We also performed mutation analysis for six causative and candidate genes for MLIDs and quantitative expression analysis using immortalized lymphocytes in MLID-positive patients.Results:Methylation analysis showed hypermethylated ZDBF2-DMR and ZNF597/NAA60-DMR, hypomethylated ZNF597-DMR in both Leu-gDNA and Buc-gDNA, and hypomethylated PPIEL-DMR in Buc-gDNA of patient 1, and hypermethylated GNAS-A/B-DMR in Leu-gDNA of patient 3. No mutations were detected in the six genes for MLIDs. Expression patterns of ZDBF2, ZNF597, and GNAS-A/B were consistent with the identified MLIDs.Conclusion:This study indicates the presence of MLIDs in TS14 patients but not in KOS14 patients.Genet Med 19 4, 476–482.

DNA Methylation in the Diagnosis of Monogenic Diseases

“…The diagnosis is reached using MS-MLPA and demonstrated as hypomethylation of the MEG3/DLK1:IG-DMR and MEG3:TSS-DMR. MLIDs have been reported in TS but not in KOS patients [60]. Recurrence risk depends on the molecular mechanism; low recurrence risk is present in case of UPD unless an inherited rearrangement of chromosome 14 is present, in case of microdeletions unless a balanced rearrangement or germinal mosaicism is present in the mother, and in case of primary methylation defects.…”

Maternally derived 15q11.2-q13.1 duplication and H19-DMR hypomethylation in a patient with Silver–Russell syndrome

“…First, we performed pyrosequencing-based methylation analyses for two DMRs responsible for SRS (H19-DMR and PEG1/MEST-DMR on chromosome 7), as previously reported. 8,9 The results showed profound hypomethylation of the H19-DMR in the patient.…”

Molecular and clinical studies in 8 patients with Temple syndrome

“…So far 22 TS14 ID patients have been described, merely 5 of them with the ID in a mosaic state. 1,5,10,26,29 In these individuals cells with a normal methylation imprint and cells with an ID coexist and the ID is therefore thought to occur due to a postfertilisation error in imprint maintenance.…”

“…Since then approximately 120 TS14 patients have been described, the majority with a UPD(14)mat and merely 22 patients with a primary imprinting defect (ID).…”

“…7 Beside maternal UPDs of chromosome 14 with and without Robertsonian translocations, paternal deletions and imprinting defects have been identified as the molecular causes of TS14. 5,8,9 Since then approximately 120 TS14 patients have been described, the majority with a UPD (14)mat and merely 22 patients with a primary imprinting defect (ID 1,5,10,11 ).…”