Proximal duplication of chromosome 14q, including the FOXG1 gene located on 14q12, is a rare condition characterised by developmental delay, dysmorphic craniofacial features, epilepsy, and severe speech delay.
Dup(14q12) harboring FOXG1 has been recently reported in individuals with developmental delay of variable severity, delayed/absent speech, and epilepsy/infantile spasms.
Duplications of 14q12 encompassing FOXG1 gene have been recently associated with developmental delay, severe speech impairment, epilepsy, aspecific neuroimaging findings and minor dysmorphisms.
A 2.0 Mb microdeletion in proximal chromosome 14q12, involving regulatory elements of FOXG1, with the coding region of FOXG1 being unaffected, results in severe developmental delay, microcephaly, and hypoplasia of the corpus callosum.
Deletions and inactivating mutations of FOXG1 have been associated with a Rett-like syndrome characterized by hypotonia, irritability, developmental delay, hand stereotypies, and deceleration of head growth.