Del 1p36 syndrome: a newly emerging clinical entity.

Monosomy 1p36 is a recently delineated contiguous gene syndrome, which is now considered to be the most common subtelomeric microdeletion syndrome. From the recent literature it appears as if 1p36 deletions account for 0.5-1.2% of idiopathic mental retardation. The deletions can be detected by high resolution cytogenetic studies in a minority of patients, and fluorescence in situ hybridisation (FISH) is required in most. The deletions' parent of origin seems still unclear, although in one large series it was shown to be maternal. 1p36 deletion syndrome is characterized by distinct craniofacial features, associated with developmental delay/mental retardation, hypotonia, muscle hypotrophy, seizures, brain abnormalities, and heart defects. To help child neurologists and other professionals in the recognition of this emerging and common chromosomal syndrome, we have reviewed published articles on patients with this deletion.