Searching chromosome mosaicisms in 45,X Turner syndrome: how relevant is it?

Jéssica Silva Soares,Renata Maria Rabello Da Silva Lago,Acácia Fernandes Lacerda De Carvalho,Laís Ribeiro Mota,Maria Betânia Pereira Toralles,Esmeralda Santos Alves

doi:10.20945/2359-3997000000403

Jéssica Silva Soares, Renata Maria Rabello Da Silva Lago + Show 4 more

Open Access

https://doi.org/10.20945/2359-3997000000403

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Abstract

To investigate the presence of chromosome mosaicism, especially for the presence of Y derived material in 45,X women with Turner syndrome (TS). FISH and PCR were performed for the presence of chromosome mosaicism and Y-derived-material and genetic findings were correlated to clinical data. Thirty-one participants were enrolled: 18 (58%) had chromosome mosaicisms (FISH), Y-derived material was found in 2. Yet, SRY primer was found with PCR in only one of them and DYZ3 was not found. The most frequent clinical findings were short or webbed neck (81,82%), high-arched palate (78%), breast hypertelorism, e cubitus valgus and genu valgus (57.6%, both), short fourth metacarpals (46.9%), epicanthic folds (43.8%), shield chest (43.8%), lymphedema (37.5%), and low set ears (34.4%). Both patients with Y-derived-material had primary amenorrhea, dyslipidemia and reached the height of 150 cm despite not treated with recombinant growth hormone (GHr). One of them showed 26% of leukocytes with Y-derived material and few clinical findings. FISH techniques proved efficient in detecting chromosome mosaicisms and Y-derived material and searching in different tissues such as mouth cells is critical due to the possibility of tissue-specific mosaicism. Phenotypical variance in TS may be a signal of chromosome mosaicisms, especially with the presence of Y-derived material.

Highlights

Full monosomy of X chromosome or structural abnormalities of one of the sex chromosomes characterize Turner syndrome (TS)
X/XX mosaicisms were seen in 13 participants, X/XX/XXX in 2 and Y-derived chromosome mosaicism in 3 participants
Eight out of eighteen participants had over 10% chromosome mosaicism, seven had 2%-10% mosaicism and three under 2%

Summary

Introduction

Full monosomy of X chromosome or structural abnormalities of one of the sex chromosomes characterize Turner syndrome (TS). Both conditions may present with mosaicisms, with two or more different cell lineages. About 50%-60% of the cases present with 45,X monosomy, 5%-10% show structural abnormalities and 30%-40% have mosaic cell lineages, including cells with structurally abnormal X and presence of Y chromosome (5%-10% of mosaic cases) (1-5). Use of molecular and cytomolecular techniques such as PCR (polymerase chain reaction) and FISH (fluorescence in situ hybridization) has been shown to perform better at detecting chromosome mosaicisms. Detecting Y-derived-material in TS is of great relevance for defining prognosis, for its presence increases risk of gonadal tumors, specially gonadoblastoma, as well as virilization and hyperandrogenism (7,8)

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