Molecular cytogenetic and phenotypic characterization of Phelan McDermid and 22q13 duplication syndrome: a case report

BACKGROUND: Phelan-McDermid syndrome (PHMDS) is a rare genetic disorder mostly caused by haploinsufficincy of SHANK3 gene, and characterized by neonatal hypotonia, developmental delay, minor dysmorphic features, seizures and behavior problems. Literature of this syndrome is scanty and confusing, and represents a challenge for pediatricians, in terms of finding the correct diagnoses. CASE PRESENTATION: In a postnatal case with hypotonia and dysmorphic features a de novo ring chromosome r(22) leading to in parallel microdeletion and micro duplication in 22q13 was diagnosed by banding cytogenetics, and further characterized in detail by molecular cytogenetic and chromosomal microarray. CONCLUSION: Here a rare PHMDS case caused by a r(22) is presented. Less than 10 comparable cases are reported in the literature. The present case highlights the importance of conducting genetic counseling and appropriate genetic tests for newborns with mild dysmorphic features.