| Distal trisomy of the short arm of chromosome 6 has characteristics of pre and postnatal growth retardation, a pattern of specific facial features (mostly of the eyes), microcephaly, and developmental delay. The duplicated region almost always includes 6pter, with proximal breakpoints ranging from 6p21 to 6p25. Interstitial duplications of 6p have also been reported with different phenotypes depending on their size and location. Most cases of distal trisomy 6p result from missegregation of a familial balanced translocation, or pericentric inversion, and are accompanied by another chromosomal imbalance. Intrachromosomal duplications or de novo translocations are also observed. |
