Comparison of early and mid-trimester amniocentesis in 1459 amniotic fluid cultures

Early amniocentesis is a new context in prenatal diagnosis. However, the consequences of this procedure are not known clearly. We compared cytogenetic results of 655 amniotic fluid samples obtained at 12-14 gestational weeks [early amniocentesis, EA] and 804 samples at 15-18 gestational weeks [mid-trimester amniocentesis, MA]. The rate of chromosomal abnormalities for early amniocentesis was 3.2% [21 cases] and for mid-trimester amniocentesis was 5.3% [43 cases] [p=0.047]. True mosaicism was seen in 2 cases MT group [p=1.000]. We did not have maternal cell contamination in either group. The ratio of repeat amniocentesis was 0.6 percent in the EA group compared with 0.2 percent in MA group [p=0.417]. Procedure-related early abortion [within the first 30 days after amniocentesis] was seen in 4 cases of EA [2.2%] and 3 cases of MA [1.5%] [p=0.719]. Hemorrhage occured in the same ratio. Intra-uterine fetal death [IUFD] was seen in 7 cases of MA, but not in any cases of EA [p=0.015]. Our findings showed comparable outcome in two method of amniocentesis, except for lower chromosomal abortion rate and IUFD

case of complete tetraploidy in amniotic fluid culture with normal karyotype in the repeat

We report a case of complete tetraploidy in amniotic fluid culture obtained at 14 weeks of pregnancy. Amniocentesis was performed in this pregnancy because of high maternal age and history of offspring with meningomyelocele. Ultrasonography at that time, revealed a single fetus with normal fetal activity and heart beat. Amniotic fluid volume was normal. The amniotic fluid obtained was yellow and clear. It was cultured in two flasks. Growth was very slow in one culture with no growth in the other. Harvest was possible after 3 weeks which revealed tetraploidy in all studied plates. Alpha feto protein of amniotic fluid was 24.1 KIU/m [normal range 11.1-48, for 15 weeks]. A repeat culture was performed at 18 weeks of gestation and a FISH analysis was performed using X and Y centromeric probes. Repeat culture revealed 46, XY pattern in 89 out of 90 studied plates. Only one plate revealed tetraploidy. Two hundred interphase cells were studied for the FISH analysis and 98% had one single X and one single Y signal. Ultrasonography at 18 weeks of pregnancy revealed no abnormality. A healthy male infant was born at term and is doing well. We conclude that abnormal karyotypes in poor growth cultures could be misleading and have to be confirmed with repeat cultures

Cytogenetic analysis of 358 bone marrow samples of suspected Acute Lymphoblastic Leukemia patients

Acute Lymphoblastic leukemia [ALL] is characterized by the accumulation of malignant, immature lymphoid cells in the bone marrow and in most cases also in peripheral blood. The disease is much more common in children than in older age group, with the incidence peaking around 3-5 years of age. Initial cytogenetic studies showed chromosomal aberrations in approximately half of all patients with ALL. Later studies and the combined use of FISH and molecular techniques have shown that the rates of detected chromosomal aberrations are 70% to 80% in these patients. The rates of detection in ALL have never been reported in Iran and we are reporting our cytogenetic findings in 358 ALL cases. We evaluated the karyotypes of 358 [21%] bone marrow samples sent to our center for cytogenetic study from patients with probable clinical diagnosis of ALL. All samples were submitted to a cell count and cultures were set up accordingly using standard protocols. Chromosomal aberrations were detected in 155 [49%] out of 314 successful cultures and the remaining 159 [51%] showed normal karyotypes. Hyperdiploidy in two forms of moderate and massive was the most common chromosomal aberration, found in 63 [40%] cases, followed by 14q abnormality in 13 [8%] and deletion of long arm of chromosome 6 in 9 [6%] of the cases. The ratios of detected numerical and structural chromosomal changes are close to and comparable with various series studies based on banding cytogenetic techniques alone. We believe that the implementation of complementary FISH and molecular cytogenetic techniques, and closer communication with the referring physicians are extremely instrumental in improving the effectiveness of cytogenetics study