Microduplication in the 2p16.1p15 chromosomal region linked to developmental delay and intellectual disability

Luca Lovrecic,Giuseppe Damante,Bertrand Isidor,Sara Bertok,Alessandra Franzoni,Borut Peterlin,Chiara Gnan,Federica Baldan

doi:10.1186/s13039-018-0388-y

Abstract

BackgroundSeveral patients with the 2p16.1p15 microdeletion syndrome have been reported. However, microduplication in the 2p16.1p15 chromosomal region has only been reported in one case, and milder clinical features were present compared to those attributed to 2p16.1p15 microdeletion syndrome. Some additional cases were deposited in DECIPHER database.Case presentationIn this report we describe four further cases of 2p16.1p15 microduplication in four unrelated probands. They presented with mild gross motor delay, delayed speech and language development, and mild dysmorphic features. In addition, two probands have macrocephaly and one a congenital heart anomaly. Newly described cases share several phenotype characteristics with those detailed in one previously reported microduplication case.ConclusionThe common features among patients are developmental delay, speech delay, mild to moderate intellectual disability and unspecific dysmorphic features. Two patients have bilateral clinodactyly of the 5th finger and two have bilateral 2nd-3rd toes syndactyly. Interestingly, as opposed to the deletion phenotype with some cases of microcephaly, 2 patients are reported with macrocephaly. The reported cases suggest that microduplication in 2p16.1p15 chromosomal region might be causally linked to developmental delay, speech delay, and mild intellectual disability.

Highlights

Several patients with the 2p16.1p15 microdeletion syndrome have been reported
As opposed to the deletion phenotype with some cases of microcephaly, 2 patients are reported with macrocephaly
The reported cases suggest that microduplication in 2p16.1p15 chromosomal region might be causally linked to developmental delay, speech delay, and mild intellectual disability

Summary

Conclusion

Despite of almost two decades of molecular karyotyping in the group of individuals with developmental delay, intellectual disability, dysmorphic features and additional clinical characteristics, novel rare copy number variations are still identified Their absence in the databases of normal copy number variation covering numerous populations renders further proof of potential significance or causality for specific phenotypes. We report in detail 4 additional cases of 2p16.1p15 microduplication, which has been reported only once in the literature so far [11]. Each novel case of such a rare CNV provides important insights for clinicians, as well as for deciphering the human genome. Together with previously reported data, our results suggest that the 2p16.1p15 microduplication might be linked to developmental delay, speech delay, mild to moderate intellectual disability, and unspecific dysmorphic features. Further cases are needed to decipher its clinical implications and decide if it represents a new clinical entity

Background

Findings