Prenatal Diagnosis of Walker-Warburg Syndrome
Rebecca Rice1, Mary Moran2, Valerie Spillane1, 1Fetal Assessment Unit National Maternity Hospital, Dublin, Ireland, 2School of Diagnostic Imaging University College Dublin, Ireland
Background:
Dandy Walker Malformation (DWM) encompasses a spectrum of abnormalities, not limited to absence/abnormality of the cerebellar vermis, dilatation of the third and fourth ventricles and enlargement of the cisterna magna. It is associated with profound cognitive and developmental impairments.
Case Report:
A 24 year old attended for a routine anatomy scan at 20 weeks gestation. She already had a healthy child and her pregnancy so far had been uncomplicated. The anatomy examination showed significant brain anomalies, namely severe bilateral ventriculomegaly of 16mm and an absent cerebellar vermis. These findings were later confirmed by a fetal medicine specialist and a provisional diagnosis of DWM made. A further ultrasound examination showed worsening ventriculomegaly of 23mm and anterior ventriculomegaly. The absent cerebellar vermis appeared more pronounced with increased cisterna magna dilatation. MR examination showed a Z-shaped brainstem, small vermis, occipital encephalocele and asymmetric orbital globes. These findings, along with the deterioration of the brain structures on subsequent ultrasound examinations, gave rise to a more accurate diagnosis of Walker Warburg Malformation, a lethal autosomal recessive genetic disorder, the most severe in a group of congenital muscular dystrophy conditions effecting 1:100,000 live births.
After consultation with a paediatric neurosurgeon and geneticist, along with worsening deterioration again on further ultrasound examinations, the couple were prepared for the likelihood of neonatal death or a profoundly dependent child. The parents declined pre-natal testing but opted for a post-mortem when the infant died at three months of age. The post-mortem confirmed the prenatal findings.
Discussion:
Whilst the outcome of this case could not have been changed, the pre-natal diagnosis prepared the parents and the multi-disciplinary teams caring for them of an adverse outcome. Also as Walker Warburg has a high recurrence rate of 1:4, the couple were also counselled on recurrence in subsequent pregnancies.