Prenatal Sonographic Features of Rare Chromosome 13 Aberrations.

Rare aberrations accounted for 24% of all chromosome 13 aberrations. Cases with mosaic monosomy of chromosome 13 and microdeletion 13q had similar abnormalities of the external genitalia and facial dysmorphia. The case with duplication 13q was very similar to the clinical features of chromosome 13 trisomy. Mosaic trisomy 13 can occur without any accompanying anatomical defects.