EP11.02: A proposed disease severity score for Trisomies 13 and 18 based on fetal MRI phenotyping

Trisomies 13 and 18 are pleiotropic diseases that constitute highly prevalent autosomal trisomy syndromes. In the past, these syndromes were deemed to be incompatible with life, however, in recent years studies have shown prolonged survival for a percentage of affected children1-2. Consequently, the question of patient-based counselling and case management arises. We aimed to identify characteristic findings on prenatal MRI that may allow for the assessment of disease severity and propose a survivability score. A retrospective review of patients with confirmed Trisomies 13 (13) and 18 (22) (gestational age 13-41 GW, mean 26.1 GW) referred for fetal MRI was conducted. In utero (26) and postmortem (15) MRI scans were phenotypically assessed. A morphology-based score estimating survivability is proposed. Anomalies potentially interfering with survival and/or associated with severe developmental impairment where rated 3 points, minor correctable features 2 points, and changes without impact on development 1 point. Following this classification, 17 cases (46%) had a score of 11-16, suggesting an unfavourable outcome. An inconclusive range between 7-10 included 14 cases (38%). 6 (16%) had a score of up to six, suggesting longer survival. The proposed MRI based phenotyping score of Trisomies 13 and 18 aims to aid physicians in counselling expectant mothers and choosing appropriate management plans. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.