New phenotypes associated with 3q29 duplication syndrome: Results from the 3q29 registry.

3q29 duplication syndrome (3q29dup) is a rare genomic disorder caused by a 1.6 Mb duplication (GRCh38 chr3:195,998,000-197,623,000). Case reports indicate the 3q29dup is likely to be pathogenic, but the full range of manifestations is not well understood.