Seckel syndrome with asymptomatic tonsillar herniation and congenital mirror movements.

Seckel syndrome is a rare genetic disorder of recessive inheritance characterized by prenatal-onset growth retardation, abnormally small head, varying degrees of mental retardation and an unusual ''beak-like'' protrusion of the nose. Additionally, it is associated with multiple organ system anomalies, including that of the central nervous system. An 8-year-old male child with typical features of Seckel syndrome and asymptomatic cerebellar tonsillar herniation diagnosed by magnetic resonance imaging associated with congenital mirror movements of the upper extremities is described. The child, additionally, had agenesis of the corpus callosum. Previously reported central nervous system anomalies associated with congenital mirror movements include corpus callosal agenesis and cranio-vertebral anomalies, both of which were present in this child. To the best of our knowledge, this is the first report of congenital mirror movements occurring in association with Seckel syndrome.