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

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.