Molecular identification of chromosome Y sequences in Brazilian patients with Turner syndrome

Abstract

The investigation of Y-specific sequences in patients with Turner Syndrome (TS) with karyotype 45,X or mosaic, has a fundamental role in the clinical management of these patients. The relationship between the presence of Y chromosome fragments and a higher risk of gonadoblastoma in TS has already been established. The aim of the study was to investigate the presence of Y-chromosome fragments in a population of 42 female Brazilian patients with TS from Mato Grosso state. Cytogenetic analysis has shown the karyotypes 45,X in 27 of them (64.3%) and mosaic in 15 (35.7%). The presence of the Y-primers SRY, DYZ3, ZFY, DYZ1, DYS1 and PABY was investigated in all patients. These markers were amplified by polymerase chain reaction (PCR) technique, using DNA genomic from peripheral blood lymphocytes. None of these patients had shown any Y-chromosome fragments when they were analysed only by the classic cytogenetic technique. The PCR analysis with the Y-specific sequences ZFY and DYZ3 were identified in two different patients (4.8%), both with karyotype 45,X. It was concluded that PCR is efficient in the investigation of hidden Y-fragments in TS patients. Therefore, this method should be included in the routine assistance of these patients.

Prevalência de sequências do Y e de gonadoblastoma em síndrome de Turner

“…Advantages of this technique include: (1) quick execution; (2) low cost; (3) simultaneous processing of multiple samples; (4) applicability in screening of a large number of patients; and (5) high sensitivity for detection of mosaicism. The use of PCR to investigate 14 Y-chromosome sequences identified a prevalence of 5%,17 value similar to that reported by a study analyzing only six sequences 14…”

“…The frequency of gonadoblastoma in TS patients with positive amplification for Y-chromosome is summarized in Table 3, with information on gonadectomy and gonadoblastoma in TS in 9 of 14 studies. The results of five studies3 , 14 , 15 , 17 , 21 are not included in Table 3 for the following reasons: (1) two studies had no information on gonadectomy and gonadoblastoma in the text3 , 21; (2) in two studies patients were scheduled for clinical follow-up17 or monitoring by a multidisciplinary team of biologist, psychologist, geneticist, endocrinologist, and gynecologist14; and (3) in one study prophylactic gonadectomy was offered to all patients with Y sequences, however, the same patients opted for regular monitoring by ultrasound and CT 15…”

“…, 15 In four TS patients, the detection of Y-chromosome sequences was identified only by PCR [karyotypes: 45,X and 46,X,i(Xq)] 1415 Thus, the inclusion of PCR technique in TS routine investigation would be indicated 14. It is noteworthy that six Brazilian studies have used only the PCR technique for the investigation of Y-chromosome sequences.…”

“…TSPY (testis-specific protein Y encoded), located in the gonadoblastoma region of the Y-chromosome (GBY) at Yp11.2, is involved in the development of gonadoblastoma and its expression was detected in this tissue and testis 2325 Regarding technique, seven studies3 , 9 – 14 , 17 used PCR alone to investigate Y-chromosome sequences in TS and in the remaining seven studies FISH was also used 1315 , 16 , 18 – 21 An intriguing finding was reported by one of these studies, which found Y-negative sequences in all 56 cases, including the five positive cases by FISH/buccal cells 20.…”

Y chromosome in Turner syndrome: review of the literature

“…This model is supported by epidemiological and morphological observations, such as the presence of immunohistochemical germ cell markers (placental alkaline phosphatase) and proto-oncogenes (c-KIT). [45][46][47] The genes SRY 16,20,32,36,[48][49][50][51][52][53][54][55][56] and DYZ3 16,32,34,[48][49][50][51]53,[55][56][57] are the sequences most commonly used in studies. Controversy still exists regarding which Y-chromosome markers are the most relevant.…”