Distribution of common chromosomal karyotypes in patients with Turner syndrome and correlation between the mean age and height standard deviation scores on diagnosis

Objective To analyze the distribution of common chromosomal karyotypes of patients with Turner syndrome(TS), and to explore the correlation between the age and height standard deviation scores(HSDS) on diagnosis. Methods Retrospective investigation was performed for the data of age and HSDS on diagnosis in 273 TS girls(≤18.0 years old)diagnosed by chromosomal karyotypes.The main statistical methods were analyzed with t-test and Pearson correlation test by using the SPSS 18.0 statistical software. Results (1)There were 4 kinds of common chromosomal karyotypes in the TS: 45, X (87/273 cases, 31.9%), 46, X, i(Xq)(43/273 cases, 15.7%), 45, X/46, X, i(Xq)(36/273 cases, 13.2%)and 45, X/46, XX(23/273 cases, 8.4%), respectively, the adolescent TS all had delayed puberty.For the cases with 45, X karyotypes, 3 cases presented mental retardation and 2 cases with organs deformity.(2)The patients with 45, X/46, X, i(Xq) karyotypes or with 46, X, i(Xq) karyotypes had the maximum(12.56 age) or the minimum(9.70 age) mean age on diagnosis, respectively, there was a significant difference between 2 groups(t=3.019, P=0.004). The maximum deviation from normal height was found in the patients with karyotypes of 46, X, i(Xq)(HSDS=-4.04), and the minimum deviation was in the patients with karyotypes of 45, X/46, XX(HSDS=-3.16), and there was a significant difference between 2 groups(t=-2.95, P=0.004). (3)More than 75.7% of TS patients was diagnosed when their heights deviated above 3 SD, and their mean age on diagnosis was 12.10 age, which was 3 years later than those patients within 2 SD.(4)There was a significant negative correlation between the age and HSDS on diagnosis in the groups of common chromosomal karyotypes[45, X、46, X, i(Xq) and 45, X/46, XX](r=-0.551, -0.560, -0.622, all P<0.01=, except for the group with the 45, X/46, X, i(Xq). Conclusions (1)In this study, the consti-tuent ratios of these 4 common chromosomal karyotypes were different from those in Europe and America's.(2)Patients with 45, X may have more severe symptoms than others.(3)The mean age on diagnosis was at least 3.0 years earlier when considered HSDS below-2.00 as an indicator for chromosomal karyotype screening, which would facilitate earlier diagnosis. Key words: Turner syndrome; Chromosomal karyotypes; Mean age; Height standard deviation scores; Early diagnosis