Microduplication Xp11.22p11.23 Syndrome

Familial and de novo recurrent Xp11.22-p11.23 microduplication has been recently identified in males and females.

Epidemiology

To date, twelve patients have been described.

Clinical description

All patients show moderate to severe intellectual deficit and speech delay. Seizures, early puberty and lower-extremity anomalies, including pes planus or cavus, 5th toe hypoplasia, and syndactyly, are common. A peculiar electroencephalographic (EEG) pattern characterized by rolandic-like spikes and/or continuous spike wave during slow sleep (CSWS) exists in childhood.

Etiology

The microduplication was identified by microarray-based comparative genomic hybridization (aCGH). Most affected females show preferential activation of the duplicated X chromosome. Duplications are mediated by nonallelic homologous recombination (NAHR) or Alu-mediated recombination.