Two cases of partial trisomy 4p and partial trisomy 14q

We present clinical and cytogenetic data on 2 cases of partial trisomy 4p and partial trisomy 14q. Both patients had an extra der(14)t(4;14)(p15.31;q12) chromosome due to a 3:1 segregation from a balanced translocation carrier mother. Array analyses indicated that their chromosomal breakpoints were similar, but there was no relationship between the 2 families. Both patients showed prominent growth retardation and psychomotor developmental delay. Other phenotypic manifestations were generally mild and variable; for example, patient 1 had a short palpebral fissure and low-set ears whereas patient 2 had a round face, asymmetric eyes, small ears, a short neck, finger/toe abnormalities, and behavioral problems.

New cytogenetically visible copy number variant in region 8q21.2

Background

Cytogenetically visible unbalanced chromosomal abnormalities (UBCA), reported for >50 euchromatic regions of almost all human autosomes, are comprised of a few megabases of DNA, and carriers are in many cases clinically healthy. It may be speculated, that some of the UBCA may be similar or identical to copy number variants (CNV) of the human genome.

Results

Here we report on a yet unreported cytogenetically visible copy number variant (CNV) in the long arm of chromosome 8, region 8q21.2, detected in three unrelated clinically healthy carriers.

Conclusion

The first description of a cytogenetically visible CNV/UBCA in 8q21.2 shows that banding cytogenetics is far from being outdated. It is a cost efficient, up-to-date method for a single cell specific overview on the whole genome, still prepared to deliver unexpected findings.