EVALUATION OF THE RELATIONSHIP BETWEEN SECOND TRIMESTER SCREENING TESTS, ULTRASOUND AND AMNIOCENTESIS FINDINGS IN THE DIAGNOSIS OF SMITH-LEMLI-OPTIZ SYNDROME IN HIGH-RISK CASES

Smith-Lemli-Opitz syndrome (SLOs) is a developmental disorder with an autosomal recessive pattern of inheritance. During pregnancy, if screening tests in the second trimester of pregnancy show an increased risk of SLOs, additional complementary studies including ultrasound and genetic testing on amniotic fluid are performed. This study aimed to investigate the relationship between second trimester screening tests, ultrasound, and amniocentesis findings in SLOs occurrence.

This study was a cross-sectional descriptive study. 44 pregnant women referred to the perinatology department of Shahid Motahari Medical Education Center with positive results for SLOs were included in the study. The correlation between second trimester screening tests, ultrasound and amniocentesis findings in confirming SLOs as well as DHCR7 gene expression in terms of common IVS8-1G>C mutation were measured.

Data showed that one of 44 cases with high-risk second trimester screening test for SLOs was positive for IVS8-1G>C mutation of DHCR7 gene.

The findings showed that although positive screening tests are new screening methods for SLOs, genetic tests are also needed for definitive diagnosis.