Prenatal diagnosis of two de novo 4q35-qter deletions characterized by array-CGH

The 4q- syndrome is a well known genetic condition caused by a partial terminal or interstitial deletion in the long arm of chromosome 4. The great variability in the extent of these deletions and the possible contribution of additional genetic rearrangements, such as unbalanced translocations, lead to a wide spectrum of clinical manifestations. The majority of reports of 4q- cases are associated with large deletions identified by conventional chromosome analysis; however, the widespread clinical use of novel molecular techniques such as array comparative genomic hybridization (a-CGH) has increased the detection rate of submicroscopic chromosomal aberrations associated with 4q- phenotype.

Herein we report two prenatal cases of 4qter deletions which presented the first with no sonographic findings and the second with brain ventriculomegaly combined with oligohydramnios. Standard karyotyping demonstrated a deletion at band q35.1 of chromosome 4 in both cases. The application of a-CGH confirmed the diagnosis and offered a precise characterization of the genetic defect.

We provide a review of the currently available literature on the prenatal diagnostic approach of 4q- syndrome and we compare our results with other published cases. Our data suggest that the identification and the precise molecular characterization of new cases with 4q- syndrome will contribute in elucidating the genetic spectrum of this disorder.