Fetal biometry in the Brachmann-de Lange syndrome.

The Brachmann-de Lange syndrome (BDLS) is diagnosed in children on the basis of a distinctive clinical phenotype which includes retarded physical growth. Because there are no genetic or biochemical tests at present, the antenatal detection of the syndrome may depend upon identification of some aspect of the phenotype in the fetus using ultrasound imaging. We studied the growth of 23 subsequently diagnosed fetuses with the BDLS using standard biometric parameters defined by prenatal ultrasound imaging. Sonographic studies were obtained through a national parents' group, the Cornelia de Lange Syndrome Foundation. Assessment of fetal growth was made using four standardized measurements: the biparietal diameter, head circumference, femur length, and abdominal circumference. These values were compared to established tables of normal fetal growth and established ratios of fetal body proportions. The cross-sectional growth curve derived using all measurements collected as a composite group indicates that growth retardation would be first detected as early as 25 weeks. In five fetuses with measurements both before and after 25 weeks of gestation, longitudinal growth curves indicated that the diagnosis of "small for gestational age" would have been suggested between 20 and 25 weeks. The mean fetal weight estimates closely followed the fifth centile curve of normal fetuses both before and after 25 weeks. Cephalic indices in BDLS fetuses indicated either frank brachycephaly (25%), or were at the upper portion of the normal range. Femur lengths were relatively short (less than 90% of their expected length) ion 4 of the 11 fetuses where such information could be obtained.(ABSTRACT TRUNCATED AT 250 WORDS)