2023 ACMG Annual Clinical Genetics Meeting Digital Edition: Poster Gallery-A supernumerary ring 9 chromosome detected in a case with ring X variant turner syndrome.

Pdf Summary

The study describes a case of a 16-month-old female with microcephaly and global developmental delay. Genetic investigation revealed a complex mosaic copy number loss involving the X chromosome and a mosaic gain in the pericentromeric region of chromosome 9. Chromosomal microarray analysis and other techniques were used to analyze the abnormalities.<br /><br />Results showed three cell lines, including a 45,X cell line, a 46,X,r(X)(p21q21) cell line, and a 47,X,r(X)(p21q21),+r(9)(p11q21) cell line. The presence of two ring chromosomes indicates multiple complex chromosome abnormalities. It is suggested that parental chromosome studies should be conducted to determine the inheritance pattern and the clinical significance of the supernumerary chromosome 9.<br /><br />The study also discusses the implications of mosaicism and the instability associated with supernumerary ring chromosomes. The presence of the XIST gene in the ring chromosome X is associated with a milder phenotype compared to derivative chromosome X without the gene. The severity of the phenotype does not necessarily correlate with the level of mosaicism.<br /><br />The authors conclude that comprehensive testing, including chromosomal microarray analysis and chromosome analysis, is necessary to accurately analyze the genomic imbalance and structural abnormalities in cases like this. The study also compares the current case to previously published cases with similar genetic abnormalities.<br /><br />Overall, this study provides insight into the complex chromosome abnormalities in Turner syndrome and highlights the importance of thorough genetic investigation in elucidating the underlying mechanisms and clinical implications.

Asset Subtitle

Presenting Author - Matthew Hoi Kin Chau, PhD; Co-Author - Elizabeth Mizerik, MS; Co-Author - Laurie Robak, MD, PhD; Co-Author - Pengfei Liu, PhD, FACMG; Co-Author - Liesbeth Vossaert, PhD, FACMG; Co-Author - Nichole Owen, PhD, FACMG;

Meta Tag

array CGH

Chromosomal Abnormalities

Cytogenetics

FISH

Co-Author Elizabeth Mizerik, MS

Co-Author Laurie Robak, MD, PhD

Co-Author Pengfei Liu, PhD, FACMG

Co-Author Liesbeth Vossaert, PhD, FACMG

Co-Author Nichole Owen, PhD, FACMG

Presenting Author Matthew Hoi Kin Chau, PhD

Keywords

microcephaly

global developmental delay

genetic investigation

X chromosome

chromosomal microarray analysis

ring chromosomes

mosaicism

XIST gene

phenotype

Turner syndrome