Complex rearrangement involving 9p deletion and duplication in a syndromic patient: genotype/phenotype correlation and review of the literature.

We describe a 7-year-old boy with a complex rearrangement involving the whole short arm of chromosome 9 defined by means of molecular cytogenetic techniques. The rearrangement is characterized by a 18.3 Mb terminal deletion associated with the inverted duplication of the adjacent 21,5 Mb region. The patient shows developmental delay, psychomotor retardation, hypotonia. Other typical features of 9p deletion (genital disorders, midface hypoplasia, long philtrum) and of the 9p duplication (brachycephaly, down slanting palpebral fissures and bulbous nasal tip) are present. Interestingly, he does not show trigonocephaly that is the most prominent dysmorphism associated with the deletion of the short arm of chromosome 9. Patient's phenotype and the underlying flanking opposite 9p imbalances are compared with that of reported patients and the proposed critical regions for 9p deletion and 9p duplication syndromes.