scholarly journals Maternal uniparental disomy of chromosome 21

2020 ◽  
Author(s):  
Keyword(s):  
Uniparental Disomy ◽  
Chromosome 21 ◽  
Maternal Uniparental Disomy

scholarly journals One test for all: whole exome sequencing significantly improves the diagnostic yield in growth retarded patients referred for molecular testing for Silver–Russell syndrome

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Robert Meyer ◽  
Matthias Begemann ◽  
Christian Thomas Hübner ◽  
Daniela Dey ◽  
Alma Kuechler ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Diagnostic Yield ◽  
Uniparental Disomy ◽  
Molecular Testing ◽  
Main Body ◽  
Comprehensive Overview ◽  
Maternal Uniparental Disomy ◽  
Whole Exome ◽  
Silver Russell Syndrome

Abstract Background Silver-Russell syndrome (SRS) is an imprinting disorder which is characterised by severe primordial growth retardation, relative macrocephaly and a typical facial gestalt. The clinical heterogeneity of SRS is reflected by a broad spectrum of molecular changes with hypomethylation in 11p15 and maternal uniparental disomy of chromosome 7 (upd(7)mat) as the most frequent findings. Monogenetic causes are rare, but a clinical overlap with numerous other disorders has been reported. However, a comprehensive overview on the contribution of mutations in differential diagnostic genes to phenotypes reminiscent to SRS is missing due to the lack of appropriate tests. With the implementation of next generation sequencing (NGS) tools this limitation can now be circumvented. Main body We analysed 75 patients referred for molecular testing for SRS by a NGS-based multigene panel, whole exome sequencing (WES), and trio-based WES. In 21/75 patients a disease-causing variant could be identified among them variants in known SRS genes (IGF2, PLAG1, HMGA2). Several patients carried variants in genes which have not yet been considered as differential diagnoses of SRS. Conclusions WES approaches significantly increase the diagnostic yield in patients referred for SRS testing. Several of the identified monogenetic disorders have a major impact on clinical management and genetic counseling.

scholarly journals Maternal Uniparental Disomy of Chromosome 20 (UPD(20)mat) as Differential Diagnosis of Silver Russell Syndrome: Identification of Three New Cases

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 588
Author(s):  
Pierpaola Tannorella ◽  
Daniele Minervino ◽  
Sara Guzzetti ◽  
Alessandro Vimercati ◽  
Luciano Calzari ◽  
...  
Keyword(s):  
Growth Retardation ◽  
Molecular Mechanisms ◽  
Uniparental Disomy ◽  
Postnatal Growth ◽  
Molecular Diagnostic ◽  
Growth Delay ◽  
Molecular Defect ◽  
Maternal Uniparental Disomy ◽  
Feeding Difficulties ◽  
Silver Russell Syndrome

Silver Russell Syndrome (SRS, MIM #180860) is a rare growth retardation disorder in which clinical diagnosis is based on six features: pre- and postnatal growth failure, relative macrocephaly, prominent forehead, body asymmetry, and feeding difficulties (Netchine–Harbison clinical scoring system (NH-CSS)). The molecular mechanisms consist in (epi)genetic deregulations at multiple loci: the loss of methylation (LOM) at the paternal H19/IGF2:IG-DMR (chr11p15.5) (50%) and the maternal uniparental disomy of chromosome 7 (UPD(7)mat) (10%) are the most frequent causes. Thus far, about 40% of SRS remains undiagnosed, pointing to the need to define the rare mechanisms in such a consistent fraction of unsolved patients. Within a cohort of 176 SRS with an NH-CSS ≥ 3, a molecular diagnosis was disclosed in about 45%. Among the remaining patients, we identified in 3 probands (1.7%) with UPD(20)mat (Mulchandani–Bhoj–Conlin syndrome, OMIM #617352), a molecular mechanism deregulating the GNAS locus and described in 21 cases, characterized by severe feeding difficulties associated with failure to thrive, preterm birth, and intrauterine/postnatal growth retardation. Our patients share prominent forehead, feeding difficulties, postnatal growth delay, and advanced maternal age. Their clinical assessment and molecular diagnostic flowchart contribute to better define the characteristics of this rare imprinting disorder and to rank UPD(20)mat as the fourth most common pathogenic molecular defect causative of SRS.

scholarly journals Maternal Uniparental Disomy of Chromosome 1 with No Apparent Phenotypic Effects

1998 ◽  
Vol 63 (4) ◽  
pp. 1216-1220 ◽  
Author(s):  
L. Leigh Field ◽  
Rose Tobias ◽  
Wendy P. Robinson ◽  
Richard Paisey ◽  
Stephen Bain
Keyword(s):  
Uniparental Disomy ◽  
Chromosome 1 ◽  
Maternal Uniparental Disomy
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