Mild fetal cerebral ventriculomegaly: prevalence, characteristics, and utility of ancillary testing in cases presenting to a tertiary referral center.

OBJECTIVE: Ventriculomegaly is the most common fetal brain anomaly identified during prenatal anatomy ultrasound. The aim of our study was to characterize cases of mild ventriculomegaly and investigate the utility of ancillary tests. METHOD: We reviewed 121 cases of mild ventriculomegaly, defined as lateral ventricle diameter of 10 to 15 mm. Characteristics of the ventricular dilation as well as each pregnancy were investigated. Ancillary tests performed included follow-up magnetic resonance imaging (MRI), chromosomal abnormality testing, and maternal serologic infection screening. The utility of each test was analyzed. RESULTS: We identified 56 cases of isolated and 65 cases of complex ventriculomegaly. Seventy-two (59.5%) were unilateral, and 49 (40.5%) were bilateral, with a mean gestational age at diagnosis of 24.5 weeks. MRI provided additional information in 3/24 (12.5%) cases of isolated ventriculomegaly compared with 18/23 (78.2%) cases of complex ventriculomegaly. Chromosomal abnormality testing identified 4/9 (44.4%) genetic abnormalities compared with 8/30 (26.7%) in cases of isolated and complex mild ventriculomegaly, respectively. Finally, maternal serology infection screening was negative in all cases. CONCLUSION: Ancillary testing is useful in isolated mild ventriculomegaly. Follow-up MRI and chromosome abnormality testing specifically provided clinically useful information. Although there were no cases of maternal infection, screening may be an important component in management. © 2017 John Wiley & Sons, Ltd.

Position of neocortical neurons transfected at different gestational ages with shRNA targeted against candidate dyslexia susceptibility genes.

Developmental dyslexia is a language learning disorder that affects approximately 4-10% of the population. A number of candidate dyslexia susceptibility genes have been identified, including DCDC2 and KIAA0319 on Chromosome (Chr) 6p22.2 and DYX1C1 on Chr 15q21. Embryonic knockdown of the function of homologs of these genes in rat neocortical projection cell progenitors by in utero electroporation of plasmids encoding small hairpin RNA (shRNA) revealed that all three genes disrupted neuronal migration to the neocortex. Specifically, this disruption would result in heterotopia formation (Dyx1c1 and Kiaa0319) and/or overmigration past their expected laminar location (Dyx1c1 and Dcdc2). In these experiments, neurons normally destined for the upper neocortical laminæ were transfected on embryonic day (E) 15.5, and we designed experiments to test whether these migration phenotypes were the result of targeting a specific type of projection neuron. We transfected litters with Dcdc2 shRNA, Dyx1c1 shRNA, Kiaa0319 shRNA, or fluorescent protein (as a control) at each of three gestational ages (E14.5, E15.5, or E16.5). Pups were allowed to come to term, and their brains were examined at 3 weeks of age for the position of transfected cells. We found that age of transfection did not affect the percentage of unmigrated neurons--transfection with Kiaa0319 shRNA resulted in heterotopia formation at all three ages. Overmigration of neurons transfected with Dcdc2 shRNA, while present following transfections at the later ages, did not occur following E14.5 transfections. These results are considered in light of the known functions of each of these candidate dyslexia susceptibility genes.