Review of Cytogenetic findings of patients with Turner Syndrome and its variants in Filipinos and the Implications in Genetic Counseling

BACKGROUND: Turner syndrome (TS) is the most common sex chromosomal abnormality in females resulting from a missing X chromosomal material. This in turn results in a range of clinical manifestations. This study aimed to provide the data on the cases of TS confirmed via chromosomal analysis in a cytogenetics laboratory in the Philippines as well as the role of genetic counseling. METHODOLOGY: A review of the karyotyping results of the Cytogenetics Laboratory, Institute of Human Genetics, National Institutes of Health, University of the Philippine Manila from 1991 to 2020. RESULTS: TS accounted for 2.64% of all the samples received from 1991 to 2020. For 30 years, the most common karyotype in TS was the classical TS or the standard monosomy 45, X noted in 195 patients or 37.69% of all patients diagnosed with TS. Mosaicism with a normal female karyotype was noted in 50 patients (9.62%). For the TS variants, the most common is isochromosome Xq seen in 125 patients (24.04%). This is followed by TS with marker chromosome in 55 patients (10.58%) and ring X chromosome in 23 patients (4.42%). Deletion Xp and deletion Xq were noted in 22 patients (4.23%) and 20 patients (3.85%), respectively. CONCLUSION: From this study, it can be noted that chromosomal analysis or standard karyotyping is a vital and useful diagnostic tool in TS. The information obtained from it may be useful in clinical decision-making of families and healthcare providers. Its importance in providing adequate genetic counseling cannot be overemphasized.