Edwards Syndrome: Echographic picture, prenatal screening in decrease of population frequency

Abstract

Introduction: Edwards Syndrome (ES) is the second most frequent one among all chromosomal aneuploidyes (ChA) after Dawn Syndrome. The population frequency of ES averages 1/7000 newborns.

Objective: To study US-screening efficiency in diagnosis of trisomy +18 in fetuses.

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Methods: Accordings to the program of mass US-screening for the period of 12 years (1987-1998) 109453 US examinations in the II trimester, 3329 amniocenteses were carried out, 180 due to ultrasound markers (UM) of ChA.

Results: In total, 11 ES fetuses with UM were diagnosed. After prenatal karyotyping of fetuses selected accordings to UM of chromosomal pathology only (mothers age less then 35), ChA were identified in 22 fetuses, 9 of them were confirmed to have trisomy +18. Among all UM identified with ES fetuses the following were the most frequent: omphalocele - 4, VSD - 3, flexor deformation of fingers - 3 and toes - 3; less frequent: chorioid plexus cysts - 2, ventriculomegaly - 2; other abnormalities - solitary detections; IUFR occurred in 6 cases, polyhydramnion - 9. Diagnostic value of UM is proposed to be estimated in scores.

Discussion: All identified ES cases in newborns and stillbirthes andprenatally diagnosticated and eliminated abnormal fetuses having been analyzed during 1987-1998. ES prevalence in Krivoy Rog was studied on this base. 109027 pregnancies outcomes were analyzed: 7 of them found to have ES (3-refused US-screening) and 7 prenatally revealed ES fetuses were eliminated and identified.

Finally, registered population frequency (FRPF) of ES in newborns accounted 1/15575 (0,64:10000). Real prevalence (RP) of ES was 1/5990 (1,67:10000) A comparative analysis of ES frequency in bom and eliminated fetuses in Krivoy Rog region and in 9 countries of the world which had been using cytogenetic monitoring for more then 10 years (selections from 9,5 mln pregnancies) showed that FRPF of ES newborns in Krivoy Rog region was less then in South America (1/12178), Spain (1/11040), Netherlands (1/8649), France (1/6317), the USA (1/6198) and greater then in Mexico (1/19660), Israel (1/22128), Hungary (1/11423). The average FRTF came to 1/11423. At the same time the average total RP of ES in countries using cytigenetic prenatal diagnosis accounted 1/5720.

Conclusions: Thus, ES fetuses are characterized by manifestative echographic phenotype, the prenatal screening of which allows 5,5 times ES FRPF decreasing on an average.