17q21.31 Microduplication Syndrome

The newly described 17q21.31 microduplication syndrome is associated with a broad clinical spectrum, of which behavioral disorders and poor social interaction seem to be the most consistent.

Epidemiology

Only five patients have been reported to date.

Clinical description

All patients have behavioral disorders suggesting that some of the genes within the duplication interval may be candidates for the autistic spectrum. Intellectual skills range from normal to mild intellectual deficiency. Other features are variable with no striking common phenotypic features.

Etiology

This microduplication syndrome was identified by microarray-based comparative genomic hybridization (aCGH). It seems reasonable to postulate that the underlying mechanism is a non-allelic homologous recombination (NAHR). Moreover, an inversion within 17q21.31, present in the Western European population at a frequency of 20%, was shown to be closely associated with the rearrangement. Parental origin was investigated in 3 patients. In all cases duplication was of maternal origin.