6q Terminal Deletion Syndrome

6q terminal deletion syndrome is marked by a characteristic facial dysmorphism, short neck and psychomotor retardation, generally associated with a range of non-specific malformations.

Epidemiology

Isolated terminal 6q deletion syndrome is very rare with less than 20 cases being reported in the literature.

Clinical description

The most frequent craniofacial anomalies include microcephaly, broad nose with prominent nasal root and bulbous nasal tip, large ears that may be malformed and low-set, and a characteristic downturned mouth. The most commonly described neurological features are psychomotor retardation, hypotonia and seizures. Retinal anomalies are also common among individuals carrying the 6q terminal deletion, highlighting the importance of ophthalmologic examinations for all patients.

Etiology

The breakpoints for the 6q terminal deletion are located between chromosome regions 6q25.3 and 6q26, within the fragile site FRA6E.