Chromosomal analysis from blood: 18 year experience of Songklanagarind Hospital

Metaphase chromosome analysis from cultured blood lymphocytes were investigated in 5,866 tests at Songklanagarind Hospital from 1990 through 2007 (18 years). Elaboration of G-bands by trypsin using Giemsa (GTG) was routinely employed with other banding techniques if required. High resolution chromosome banding was performed in suspected cases of structural chromosome abnormality. Successful studies were obtained in 5,665 tests (96.4 %) and 1,680 tests (28.7 %) were found to have chromosomal abnormalities. The failure rate was 3.4 % (201 tests). Fifty duplicated tests were discarded of the 1680 abnormal results, leaving 1,630 cases with abnormal chromosomes. Of 1,630 cases, Down, Edwards, and Patau syndromes were found in 933 (57.2 %), 87 (5.3 %) and 80 (4.9 %) cases, respectively. There were 215 cases with sex chromosome abnormalities (13.2 %), including 188 cases with Turner syndrome, 18 cases with Klinefelter syndrome, 6 cases with XXX syndrome and 3 cases with XYY syndrome. Androgen insensitivity syndrome (female with 46,XY) was found in 23 cases, and structural chromosome abnormalities were found in 222 cases (13.6 %). The remainder (70 cases/4.3 %) was composed of microdeletion, marker chromosome, fragile X syndrome and rare trisomy. To the best of our knowledge, this study is the largest group of chromosome analysis results reported from Thailand. These findings can be available to provide the database for genetic counseling.