16p13.11 Microduplication Syndrome

16p13.11 microduplication syndrome is a recently described syndrome associated with variable clinical features including behavioral abnormalities, developmental delay, congenital heart defects and skeletal anomalies.

Epidemiology

It has been clinically and molecularly characterized in fewer than 20 patients.

Clinical description

Behavioral abnormalities include attention deficit/hyperactivity disorder, aggression and disruptive temperament, and autistic spectrum disorders. Skeletal manifestations include hypermobility, craniosynostosis and polydactyly.

Etiology

This syndrome is caused by interstitial duplications encompassing 16p13.11. The size of the rearrangements is variable. The duplications were characterized by comparative genomic hybridization (CGH) microarray and fluorescence in situ hybridization (FISH). The underlying mechanism is non-allelic homologous recombination (NAHR). The microduplications appear de novo or are inherited from mildly affected or completely normal parents, suggesting that the microduplication has incomplete penetrance and variable expressivity. Two genes, NDE1 (nudE nuclear distribution gene E homolog 1) and NTAN1 (N-terminal asparagine amidase) included in the duplicated region may contribute to the neurobehavioral phenotype. As the duplication is present in phenotypically normal parents of patients, as well as in the general population, the clinical significance of the 16p13.11 microduplication is still unclear.