Abstract

REIS, Ana Paula et al. Morphological and biochemical changes in trisomy 21. Arq Med [online]. 2015, vol.29, n.4, pp.88-92. ISSN 2183-2447.

Overview: Trisomy 21 (T21) is the most common aneuploidy, with a prevalence of 1/670 births. It is the leading cause of moderate to severe intellectual deficit and is associated with several birth defects, cardiovascular malformations being the most frequent. The objective of this work is to characterize the morphological and biochemical changes in the cases of T21. Material and Methods: Prospective study performed at our Hospital between 1998 and 2008, for evaluation of cases with positive biochemical screening for T21. We also analyzed the results of invasive tests in the same period and reviewed all the clinical files diagnosed with T21 in this exam, as well as the clinical files of mothers whose newborns were diagnosed with T21. Results: In this period 12163 screenings were conducted. We identified 18 cases of T21. There were 2 false-negative results, and the detection rate of screening was 88.9%. The median MoM's of biochemical markers in pregnant with affected fetuses was: 0,735 of AFP, 0,685 of µE3 and 2,54 of βHCG. Fifteen of 18 couples chose to terminate the pregnancy. Three infants were born with T21. The anomalies in affected fetuses were essentially of the external habit, namely the existence of transverse palm creases of one or both hands and craniofacial abnormalities. The most common internal habit changes were cardiovascular malformations, namely ventricular septal defect (Vsd). Discussion: In this study the detection rate of screening was high. The majority of the couples chose to terminate the pregnancy. Most fetuses and newborns affected presented subtle morphological features, difficult to detect by ultrasound, enhancing the importance of biochemical screening.

Keywords : biochemical screening; morphological changes; second trimester; trisomy 21.

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