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[Analysis of specific sequences in female patients with Turner syndrome--initial study]
R Vodicka1, R Vrtĕl, K Adamová
1Ustav lékarské genetiky a fetální medicíny LF UP a FN, Olomouc. vodickar@fnol.cz
Background:
DNA sequences from chromosome Y can cause gonadoblastoma development in patients with Turner syndrome (TS). Estimated risk is about 30%. The aim of the study is detection of Y-sequences of DNA level, calculation of mosaicism and its cytogenetic location. Clinical result of the study is the recommendation to gonadectomy of proved positive patients.
Methods And Results:
Samples from 110 patients were collected. The PCR method and analysis of products on agarose gel was compared with analysis of DNA fragments from quantitative fluorescent (QF) PCR on capillary electrophoresis. The loci DYZ3, AMGX/Y and SRY were used for detection. The method QF PCR was effected for DYZ3 and AMGX/Y loci. The positive cases were examined by FISH method. Five (4.5%) and 3 (2.7%) positive cases were detected in DYZ3 and SRY resp. loci by electrophoresis on agarose gel. Seventeen (15.5%) and 7 (6.4%) positive cases were detected in DYZ3 and AMGX/Y resp. by capillary electrophoresis. The estimated mosaicism ranged from 1:5 to 1:100,000.
Conclusions:
QG PCR is the most sensitive method for diagnostics of Y-sequences. Simultaneously the incidence of Y-positive cells can be estimated. The positive cases with marker in karyotype were confirmed by FISH.
Insights
Quantitative fluorescent PCR (QF PCR) is the most sensitive method for detecting Y-chromosome DNA sequences in Turner syndrome patients, aiding in gonadoblastoma risk assessment. This method allows for mosaicism estimation, guiding clinical decisions like gonadectomy.
Area of Science:
- Genetics
- Molecular Biology
- Oncology
Context:
- Turner syndrome (TS) patients have an elevated risk (approx. 30%) of gonadoblastoma due to Y-chromosome DNA sequences.
- Early and accurate detection of Y-sequences is crucial for risk stratification and clinical management.
Purpose:
- To detect Y-chromosome DNA sequences at the DNA level in Turner syndrome patients.
- To calculate the extent of mosaicism and determine the cytogenetic location of Y-sequences.
- To compare the sensitivity of different molecular detection methods.
Summary:
- Quantitative fluorescent PCR (QF PCR) demonstrated higher sensitivity in detecting Y-sequences (DYZ3, AMGX/Y loci) compared to traditional gel electrophoresis.
- QF PCR identified a higher prevalence of Y-positive cases (15.5% for DYZ3, 6.4% for AMGX/Y) than gel electrophoresis (4.5% for DYZ3, 2.7% for SRY).
- Mosaicism levels were estimated to range from 1:5 to 1:100,000, with positive cases confirmed by Fluorescence In Situ Hybridization (FISH).
Impact:
- QF PCR is recommended as the most sensitive diagnostic method for Y-sequence detection in Turner syndrome.
- Accurate detection and mosaicism estimation inform clinical decisions, including the recommendation for gonadectomy in positive cases.
- This study refines the diagnostic approach for Turner syndrome patients at risk of gonadoblastoma.