Prenatal diagnosis of pure 1p36 terminal deletion by chromosome microarry analysis: clinical report of 3 new cases and review of the literature Running title: Prenatal diagnosis of 1p36 terminal deletion

Objective: we objective to present the experience on prenatal diagnosis of 1p36 terminal deletion, and further delineated the fetal presentation of the syndrome. Materials and methods: This was a retrospective analysis of three new prenatal cases with pure 1p36 terminal deletion detected by chromosome microarray analysis (CMA) at a single Chinese medical center. We also reviewed 11 published prenatal cases with similar deletion sizes. Clinical data of all cases including indications for invasive testing, sonographic findings, maternal factors, and pregnancy outcomes were reviewed and analyzed. Results: Three new cases with pure 1p36 terminal deletion were prenatal diagnosed by CMA, the sizes of the deletion were 1.3 Mb, 5.0 Mb, and 4.9 Mb respectively. All cases were detected because of abnormal ultrasound findings, including central nervous system (CNS) abnormalities, congenital heart disease (CHD) and fetal growth restriction. Two pregnancies were terminated, and one was live-born but died three months after birth. Conclusions: The 1p36 terminal deletion results in many clinical manifestations, but the specificity of clinical features are not high. Prenatal sonographic findings such as CNS, CHD may act as suggestive signs of 1p36 deletion or other microdeletion/duplication syndromes.