7q35q36.3 deletion and concomitant 20q13.2q13.33 duplication in a newborn: familiar case

Array-CGH is a powerful tool in identifying and characterizing complex genomic rearrangements smaller than 5-10 megabase (Mb), for which classical cytogenetic approaches are not sensitive enough. The use of Array-CGH has increased of 10-20% the detection rate of unbalanced cryptic rearrangements, such as deletions and/or duplications.

We present here the first report of a patient with 7q35q36.3 microdeletion and concomitant 20q13.2q13.33 microduplication detected by array-CGH and confirmed by reiterative FISH experiments associated with dysmorphism, development delay, Long QT syndrome (LQTS), complex congenital heart disease, pulmonary hypertension, hypotonia, respiratory distress, cognitive deficit.

We proved that this unbalanced rearrangement was due to an adjacent-1 segregation that occurred in the mother, carrier of a balanced translocation between chromosomes 7 and 20. The same unbalanced rearrangements were also found in the proband's maternal uncle, who had been given a clinical diagnosis of Dandy-Walker/Rubinstein-Taybi syndromes in the past. Given the above-mentioned observations, the proband's uncle is not affected by Dandy-Walker/Rubinstein-Taybi syndromes, but by a genomic syndrome highlighted by array-CGH.

The Array-CGH allowed us to understand that the loss of several genes is expressed with clinical manifestations due to the concomitance of several syndromes, each related to the malfunction of a "specific disease gene". For these reasons, the genotype-phenotype correlation in these cases is more complex. This study confirms that the array-CGH is useful in identifying pathologies that were considered idiopathic until a few years ago.