2q23.1 Microdeletion Syndrome

The newly described 2q23.1 microdeletion syndrome includes severe intellectual deficit with pronounced speech delay, behavioral abnormalities including hyperactivity and inappropriate laughter, short stature and seizures.

Epidemiology

To date, fifteen patients have been reported.

Clinical description

Dysmorphic features include microcephaly, wide and open mouth, a tented upper lip, and prominent incisors. The majority of cases present with stereotypic repetitive behavior, a disturbed sleep pattern and a broad-based gait. Skeletal abnormalities include generalized brachydactyly with small hands and feet.

Etiology

The microdeletion was identified by microarray based comparative genomic hybridization (aCGH). The size of the deletions is variable; the critical region includes a single gene, MBD5. Another gene, EPC2, is deleted in patients who have a broader phenotype than those with a deletion of MBD5 only.