Mosaic Potocki-Lupski Syndrome Due to a Supernumerary Marker Chromosome Containing <i>RAI1</i>

Abstract

Potocki-Lupski syndrome<strong> </strong>(PTLS) is a recurrent microduplication syndrome characterized by developmental delay, behavioral abnormalities, mildly dysmorphic facial features, hypotonia, and sleep disorders. We report here a 3-year-old girl diagnosed with mosaic PTLS harboring a supernumerary marker chromosome containing the <em>RAI1</em> (retinoic acid induced 1) gene. Cytogenetic testing, including chromosomal microarray, karyotype, and FISH analysis, identified a ring chromosome containing portions of chromosomes 14 and 17 in 85% of cells. Clinical features of this individual included atypical facies with frontal bossing, bitemporal narrowing, prominent cupped ears, and mild speech delay. Presented here is a novel case of PTLS associated with mosaic gains of chromosomes 14 and 17. As small supernumerary marker chromosomes (sSMCs) involving non-acrocentric chromosomes are rare, this case contributes to our understanding of phenotypic spectrum associated with sSMC(17).