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Moch J, Radtke M, Gburek-Augustat J, Karnstedt M, Schönnagel S, Drukewitz SH, Pilgram L, Hentschel J, Schumann I. Case report: Complete paternal isodisomy on chromosome 18 induces methylation changes in PARD6G-AS1 promotor in a case with arthrogryposis. Front Genet 2023; 14:1297754. [PMID: 38188501 PMCID: PMC10768175 DOI: 10.3389/fgene.2023.1297754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/28/2023] [Indexed: 01/09/2024] Open
Abstract
Uniparental disomy (UPD) is the inheritance of both alleles of a chromosome from only one parent. So far, the detection of UPDs in sequencing data is not well established and a known gap in next-generation sequencing (NGS) diagnostics. By developing a new tool for UPD detection, we re-evaluated an eight-year-old individual presenting with scoliosis, muscle weakness and global developmental delay. Previous panel analysis identified a homozygous likely pathogenic loss-of-function variant in the PIEZO2-gene associated with arthrogryposis (OMIM # 617146). Interestingly, during a re-evaluation process, we identified a region of homozygosity (ROH) covering over 95% of chromosome 18. Segregation and microsatellite analysis within the family revealed that only the father is a heterozygous carrier of the variant in PIEZO2 and confirmed paternal uniparental isodisomy (iUPD) on chromosome 18 in the individual. Further methylation analysis indicated demethylation of the promotor region of PARD6G-AS1, which is described to be maternally imprinted and could possibly influence the individuals' phenotype. Our report describes the first complete iUPD on chromosome 18 and highlights that UPDs can be a cause for homozygous pathogenic variants, which reduces the risk of reoccurrence in case of a new pregnancy in comparison to an autosomal recessive inheritance trait significantly.
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Affiliation(s)
- Johanna Moch
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Maximilian Radtke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Janina Gburek-Augustat
- Division of Neuropaediatrics, Hospital for Children and Adolescents, University of Leipzig Medical Center, Leipzig, Germany
| | - Maike Karnstedt
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Senta Schönnagel
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Stephan H. Drukewitz
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Laura Pilgram
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Julia Hentschel
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Isabell Schumann
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
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Chen CP, Wu FT, Pan YT, Chern SR, Wu PS, Chiu CL, Lee CC, Chen WL, Wang W. Prenatal diagnosis of mosaic trisomy 18 and maternal uniparental disomy 18 by amniocentesis in a pregnancy associated with cytogenetic discrepancy in various tissues and a favorable fetal outcome. Taiwan J Obstet Gynecol 2023; 62:606-610. [PMID: 37407205 DOI: 10.1016/j.tjog.2023.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2023] [Indexed: 07/07/2023] Open
Abstract
OBJECTIVE We present prenatal diagnosis of mosaic trisomy 18 and maternal uniparental disomy (UPD) 18 in a pregnancy with a favorable fetal outcome. CASE REPORT A 34-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age, and the result was 47,XY,+18 [4]/46,XY [25] in cultured amniocytes. Simultaneous array comparative genomic hybridization (aCGH) on uncultured amniocytes revealed 65% mosaicism for trisomy 18. Prenatal ultrasound was normal. She consulted our hospital and underwent repeat amniocentesis at 22 weeks of gestation, and the result revealed a karyotype of 47,XY,+18 [9]/46,XY [12] in cultured amniocytes. Simultaneous aCGH on uncultured amniocytes revealed arr 18p11.32q23 × 2.4 (log2 ratio = 0.3) consistent with 40% mosaicism for trisomy 18. Parental karyotypes were normal. Quantitative fluorescent polymerase chain reaction (QF-PCR) analysis on the DNA extracted from parental bloods and uncultured amniocytes confirmed maternal uniparental heterodisomy of chromosome 18. At 26 weeks of gestation, she underwent the third amniocentesis which revealed a karyotype of 47,XY,+18 [7]/46,XY [19] in cultured amniocytes. Simultaneous aCGH on uncultured amniocytes revealed arr 18p11.32q23 × 2.4 (log2 ratio = 0.27) consistent with 40% mosaicism for trisomy 18. Interphase fluorescence in situ hybridization (FISH) on uncultured amniocytes revealed 38% (38/100 cells) mosaicism for trisomy 18. The woman was advised to continue the pregnancy, and a 2620-g phenotypically normal male baby was delivered at 40 weeks of gestation. At birth, the karyotypes of cord blood, umbilical cord and placenta were 47,XY,+18 [14]/46,XY [26], 47,XY,+18 [9]/46,XY [31] and 47,XY,+18 (40/40 cells), respectively. When follow-up at age 2½ months, the neonate was phenotypically normal. The peripheral blood had a karyotype of 47,XY,+18 [28]/46,XY [12], and interphase FISH analysis on buccal mucosal cells detected 6.4% (7/93 cells) mosaicism for trisomy 18, compared with 0% (0/100 cells) in the normal control. When follow-up at age seven months, the neonate was normal in development, and the peripheral blood had a karyotype of 47,XY,+18 [18]/46,XY [22]. CONCLUSIONS Mosaic trisomy 18 at amniocentesis can be associated with cytogenetic discrepancy in various tissues, UPD 18 and a favorable fetal outcome. Prenatal diagnosis of mosaic trisomy 18 should alert the possibility of UPD 18 and include UPD testing.
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Affiliation(s)
- Chih-Ping Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Medical Laboratory Science and Biotechnology, College of Medical and Health Science, Asia University, Taichung, Taiwan.
| | - Fang-Tzu Wu
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Yen-Ting Pan
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Schu-Rern Chern
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | | | - Chien-Ling Chiu
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | - Chen-Chi Lee
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Wen-Lin Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Wayseen Wang
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
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