5q14.3 Microdeletion Syndrome

The newly described 5q14.3 microdeletion syndrome includes severe intellectual deficit with no speech, stereotypic movements and epilepsy.

Epidemiology

To date, fourteen patients have been reported.

Clinical description

Miscellaneous dysmorphic facial features are present in all cases, but some common features are noticed, high and wide forehead, pronounced eyebrows, anteverted nostrils, short and prominent philtrum, down-turned corners of the mouth and small chin. Stereotypic movements and poor eye contact are present in many patients, suggesting the diagnosis of autism spectrum disorder. In most patients brain imaging is reported to be abnormal, including anomalies of the corpus callosum, enlarged ventricles, periventricular white matter, hyperintensities and cortical atrophy.

Etiology

The microdeletion was identified by microarray-based comparative genomic hybridization (CGH). The size of deletions varies, the minimal common deleted region encompasses only MEF2C, suggesting that haploinsufficiency of MEF2C is responsible for the phenotype.