Complex sSMC Involving X and Y Chromosomes in two Patients with 45,X/46,X,+mar Karyotype

Miriam Beatriz Goulart,Marcia Gonçalves Ribeiro,Monique Oliveira Freitas,Evelyn Kahn,Isaias Soares Paiva,Sandra Alves Peixoto Pellegrini,Marilia Martins Guimarães,Maria Cecilia Menks Ribeiro

doi:10.34257/gjmrfvol20is13pg19

Abstract

Complex small supernumerary marker chromosomes (sSMCs) consist of chromosomal material derived from two or more different chromosomal regions and constitute one of the smallest subsets of sSMC. Most of complex sSMCs are represented by a der(22)t(11;22) in Emanuel syndrome. As far as we know, only one recent report has described sSMCs involving simultaneously X and Y chromosomes in Turner Syndrome. We report two patients, a female and a male, both with a complex sSMC derived from X and Y chromosomes in mosaic with a 45,X cell line. In both patients, the marker chromosomes were early replicating and the XIST gene was absent. FISH and PCR confirmed the presence of Yp loci (TSPY, AMGY, SRY, DYZ3), and negative for DYZ1. The DAZ4 sequence was present only in patient 1.Our findings suggested that complex sSMC involving X and Y chromosome could be a kind of sSMC of the gonosomes.

Highlights

More different chromosomal regions and constitute one of the 82.2%) (Liehr et al, 2013)
SSMC can be present in numerically abnormal karyotype like in a Turner syndrome (TS) karyotype (45,X/46,X,+mar), leading to female or male phenotypes (Liehr et al, 2007; Wang et al, 2017)
In TS, the small supernumerary marker chromosome (sSMC) are derived from one of the gonosomes in more than 99% of the cases; there are exceptional reports on sSMC derived from autosomes

Summary

Introduction

More different chromosomal regions and constitute one of the 82.2%) (Liehr et al, 2013). A female and a male, both (excluding ES) showed that 36% of them were de novo, with a complex sSMC derived from X and Y chromosomes in and the remainder (64%) were inherited from a balanced mosaic with a 45,X cell line. In both patients, the marker translocation in one parent. We report two mosaic patients, a TS patient and an unidentified syndrome male, with a 45,X cell line and a cell line with complex sSMC involving X and Y chromosomes, characterized by Fluorescence in situ hybridization (FISH) and Polymerase Chain Reaction (PCR)

Methods

Findings

Conclusion