Reference Work Entry

Encyclopedia of Molecular Mechanisms of Disease

pp 503-504

Deletion of 18q

  • A. J. LarnerAffiliated withCognitive Function Clinic, Walton Centre for Neurology and Neurosurgery


Chromosome 18q deletion syndrome; de Grouchy syndrome; 18q- syndrome; OMIM#601808

Definition and Characteristics

Deletion of the long arm of chromosome 18 produces a multiple-anomaly mental retardation syndrome of variable phenotype encompassing: learning disability, sometimes with non-development of language, short stature, and variable dysmorphism, such as microcephaly, mid-facial hypoplasia, prominent antihelix, and long tapering fingers [1]. Hearing loss, sensorineural or conductive, is common, the latter due to congenital aural atresia. Neurological symptoms and signs, such as hypotonia, nystagmus and incoordination, are also common [2]. Movement disorders such as tremor and dystonia have been reported, as have seizure disorders of variable semiology, including complex partial seizures with prominent autonomic features, apnoeic seizures, and benign focal seizures, most usually with childhood onset but sometimes presenting in adults [3]. ...

This is an excerpt from the content