Reports in the medical literature of supernumerary ring chromosome 20 are rare. Previous studies of duplication and triplication involving the pericentromeric regions of chromosome 20 have shown that carriers present with various clinical features that may include developmental delay, subtle facial dysmorphisms, and abnormalities of the brain, skull and hands. The gene ASXL1 has been implicated in the pathogenicity of reported copy number gains. Conversely, heterozygous loss-of-function variants in ASXL1 are associated with Borhing-Opitz syndrome, which has overlapping clinical features with gains involving this gene. In this study, we present a 2-year-old boy with developmental delay, brain and skull abnormalities, and abnormal movements. Whole exome sequencing did not identify any variants of significance. Cytogenomic SNP microarray analysis was then preformed and showed a complex structural rearrangement suggestive of a ring chromosome 20. A total of three gains were identified with duplication of the region from 20p11.21 to q11.21 and from q11.2 to q11.22 and triplication of the region from q11.22 to q11.23. Subsequent chromosome analysis confirmed the presence of a small supernumerary ring chromosome 20. qPCR was performed on parental specimens and suggested that the ring chromosome was a de novo event in this individual. Further investigation of the approximately 150 genes included in the various copy number gains showed that ASXL1 was present in the largest duplication of the ring that also included the centromere. This study provides further evidence that copy number gains involving ASXL1 result in a clinical presentation with features overlapping Borhing-Opitz syndrome.