Neonate with ‘rocker-bottom’ feet: what to do when it is not Edwards syndrome

Neonates born with congenital vertical talus (‘rocker-bottom foot’) are challenging to diagnose and manage. The immediate management is generally based on assessing for Edwards syndrome (trisomy 18) or other similar severe life-limiting chromosomal disorders when there are dysmorphic features suggestive of a genetic syndrome, and no clear neurological focus such as a neural tube defect or spinal muscular atrophy disorder. Often the initial fluorescent in situ hybridisation genetic testing is reported as normal, appearing to exclude a trisomy diagnosis. We use two similar neonatal case scenarios with different diagnoses to discuss the next steps in genetic testing and the use of microarray, karyotyping and whole exome sequencing tools in managing these complex cases.