Prenatal diagnosis of inverted duplicated 8p.

The phenotype of inverted duplicated 8p, region 8p11.2-p23, reported in children and adults, includes: severe mental retardation, minor facial anomalies, agenesis of corpus callosum, and other malformations including those of heart and kidneys. We report on the prenatal diagnosis of 2 cases of inverted duplication 8p. Both cases were ascertained by abnormal level 2 ultrasound findings. Case 1 presented at 16.5 weeks of gestation with massive distention of the fetal bladder, bilateral hydronephrosis, abnormality of the lower lumbar spine, absence of the sacral spine and a Dandy-Walker variant (interhemispheric cyst and enlarged third ventricle). Case 2 presented at 30 weeks of gestation with agenesis of corpus callosum, slightly enlarged lateral ventricles, interhemispheric cyst and enlarged third ventricle, and possible coarctation of the aorta. The intracranial and cardiac anomalies were confirmed and further defined after delivery. Cytogenetic analysis in both cases showed additional material on 8p. In both cases, fluorescence in situ hybridization (FISH) defined the abnormal chromosome, as a pseudodicentric chromosome with duplication of the short arm from centromere to p23 and deletion from p23 to pter. Our findings support those of prior reports of the inverted duplicated 8p chromosome with multiple anomalies and add prenatal findings to our knowledge. Copyright 2000 Wiley-Liss, Inc.