First‐Trimester Sonographic Diagnosis of Holoprosencephaly

Abstract

Objective. To study the value of choroid plexus dysmorphology as a screening tool for the firsttrimester sonographic diagnosis of holoprosencephaly in a high-risk population. Methods. A total of 378 consecutive pregnancies undergoing chorionic villus sampling between 11 and 14 weeks' gestation were scanned before the procedure, following the recommendations of the Fetal Medicine Foundation (London, England). A cross-sectional view of the fetal brain, including the visualization of both choroid plexuses (the "butterfly" sign), was obtained in all cases. Results. There were 3 cases in which the butterfly sign was not identified. In these cases, the first-trimester diagnosis of holoprosencephaly was confirmed by the presence of a single monoventricular cavity and fused thalami. Two of these fetuses had features of facial dysmorphism at the time of presentation and 2 had extracranial anomalies, including a cystic hygroma in 1 and a small omphalocele and polydactyly in another. Chromosomal analysis showed trisomy 13 in 2 cases and a ring chromosome 13 in the other. Conclusions. This series suggests that failure to identify the butterfly sign is a warning sign of holoprosencephaly in the first trimester. Systematic identification of the butterfly sign at the time of sonographic assessment of nuchal translucency provides a valuable tool for the early screening of holoprosencephaly. Key words: brain anomalies; choroid plexus; first trimester; holoprosencephaly; prenatal sonography. MD, Fetal Medicine Center, Clinica Las Condes, Casilla 208, Santiago 20, Chile. E-mail waldosep@hotmail.com. Abbreviations CVS, chorionic villus samplingoloprosencephaly is a severe brain anomaly characterized by different degrees of fusion of the lateral ventricles resulting from failure of the prosencephalon to cleave during early embryogenesis. 1 This condition is invariably associated with a wide range of midfacial defects ranging from a single incisor to cyclopia. 2 Prenatal diagnosis of holoprosencephaly is usually made in the second trimester by the sonographic demonstration of fused lateral ventricles, no visible midline structures, and fusion of the thalami. 3 Recently, first-trimester sonographic screening for chromosomal abnormalities by measuring the nuchal translucency thickness at 11 to 14 weeks' gestation 4,5 has been increasingly incorporated into routine clinical practice. An important advantage of this examination is the possibility of an early examination of the fetal anatomy for major structural defects. [4][5][6]

Prenatal Detection of Fetal Anomalies at the 11- to 13-Week Scan—Part I: Brain, Face and Neck

“…2). 16 This view provides important information regarding the cleavage of the prosencephalon, as the presence of the 'butterfly' sign rules out a serious condition, such as holoprosencephaly by demonstrating the midline and two lateral cerebral ventricles.…”

“…8). 16,24 A small biparietal diameter as an early sonographic feature of holoprosencephaly has been recently emphasized. 24 Prenatal karyotyping should be considered in these cases due to the strong association with chromosomal abnormalities, particularly trisomy 13.…”

Ultrasound and fetal diagnosis

“…A cross-sectional view of the fetal brain, including visualization of the choroid plexus in both lateral ventricles (the 'butterfly' sign), is important to carry out because the absence of the 'butterfly' sign suggests holoprosencephaly [30 ]. Multiple abnormalities may be consistent with a syndrome.…”

The Use of a High Frequency Linear Transducer in the Assessment of Fetal Anatomy at the Routine 11 to 13 + 6-Week Scan among Chinese Population

“…In the era of non-invasive prenatal testing (NIPT), all pregnant women should still be offered an ultrasound examination in the first trimester [1] with the benefits of early detection and exclusion of many major anomalies [2]- [4], some of which are either lethal or associated with severe handicap that may warrant the discussion of an earlier and safer termination of pregnancy with the pregnant women [5] [6]. Combining transvaginal approach with transabdominal sonography had increased the successful visualization rate of fetal anatomy from 72% to 86% [7].…”