Inherited dup(17)(p11.2p11.2): expanding the phenotype of the Potocki-Lupski syndrome.

Potocki-Lupski syndrome (PTLS, OMIM: 610883) is a microduplication syndrome characterized by infantile hypotonia, failure to thrive, cardiovascular malformations, developmental delay, intellectual disability, and behavior abnormalities, the latter of which can include autism spectrum disorder. The majority of individuals with PTLS harbor a de novo microduplication of chromosome 17p11.2 reciprocal to the common recurrent 3.6 Mb microdeletion in the Smith-Magenis syndrome critical region. Here, we report on the transmission of the PTLS duplication across two generations in two separate families. Individuals in these families presented initially with developmental delay, behavior problems, and intellectual disability. We provide a detailed review of the clinical and developmental phenotype of inherited PTLS in both families. This represents the second report (second and third families) of PTLS in a parent-child pair and exemplifies the under-diagnosis of this and likely other genetic conditions in adults with intellectual disability and/or psychiatric disorders.