16p13.11 Microdeletion Syndrome

16p13.11 microdeletion syndrome is a recently described syndrome characterized by developmental delay, microcephaly, epilepsy, short stature, facial dysmorphism and behavioral problems.

Epidemiology

It has been clinically and molecularly characterized in fewer than 15 patients.

Clinical description

Facial features include down-slanting palpebral fissures, short nose, low-set ears, wide mouth and thin upper lip. Variable congenital anomalies can also be observed.

Etiology

This syndrome is caused by an interstitial deletion encompassing 16p13.11. The deletions were characterized by comparative genomic hybridization (CGH) microarray and fluorescence in situ hybridization (FISH). The underlying mechanism is non-allelic homologous recombination (NAHR). Microdeletions appear de novo or are inherited from mildly affected or completely normal parents in an autosomal dominant manner, suggesting that the microdeletion has incomplete penetrance and variable expressivity. Two genes within the deleted region, NDE1 (nudE nuclear distribution gene E homolog 1) and NTAN1 (N-terminal asparagine amidase) may contribute to the neuro-cognitive phenotype.