14q12 Microdeletion Syndrome

14q12 microdeletion syndrome is a recently described syndrome characterized by severe intellectual deficit, with a normal neonatal period, followed by a phase of regression at the age of 3-6 months.

Epidemiology

It has been clinically and molecularly characterized in 3 patients so far.

Clinical description

The neurological picture evokes the congenital variant of atypical Rett syndrome (see this term). The phenotype includes other features: postnatal growth retardation and microcephaly, hypotonia, epilepsy, stereotypic movements and feeding problems. Dysmorphic features associate prominent metopic suture, bilateral epicanthic folds, bulbous nasal tip, tented upper lip, everted lower lip and large ears.

Etiology

This syndrome is caused by an interstitial deletion encompassing 14q12. These de novo deletions were characterized by comparative genomic hybridization (CGH) microarray and fluorescence in situ hybridization (FISH). They have a variable size and include FOXG1 as the gene responsible for the intellectual deficit and severe microcephaly.