First-trimester sonographic diagnosis of holoprosencephaly: value of the "butterfly" sign.
OBJECTIVE
To study the value of choroid plexus dysmorphology as a screening tool for the first-trimester 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.
Sepulveda
Waldo
W
Fetal Medicine Center, Department of Obstetrics and Gynecology, Clinica Las Condes, Santiago, Chile. waldosep@hotmail.com
Dezerega
Victor
V
Be
Cecilia
C
D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging; D015193:Chorionic Villi Sampling; D002831:Choroid Plexus / Q000000981:diagnostic imaging*; D005260:Female; D016142:Holoprosencephaly / Q000175:diagnosis / Q000000981:diagnostic imaging*; D006801:Humans; D007621:Karyotyping; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D016216:Ultrasonography, Prenatal