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

Abstract

Keywords:Chromosome 9p complex rearrangement Array-CGH FISH 9p deletion syndrome 9p duplication syndrome Phenotype-genotype correlationWe 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.

Diagnostic Approach to Microdeletion Syndromes Based on 22q11.2 Investigation: Challenges in Four Cases

“…Some studies report patients with a 9p deletion presenting with facial asymmetry, hypertelorism, short palpebral fissure, strabismus, asymmetric and dysmorphic ears, wide nasal bridge, long nasal filter, high palate, malocclusion, and psychomotor retardation [Freitas et al, 2011;Recalcati et al, 2012;Spazzapan et al, 2016]. Whereas patients with a 6p duplication are reported having language disorders, motor delay, and intellectual deficit [Vermeesch et al, 2004].…”

Chromosome 9p terminal deletion in nine Egyptian patients and narrowing of the critical region for trigonocephaly

“…This patient had the clinical picture of 9p deletion syndrome including trigonocephaly, suggesting that the critical region for the clinical picture of 9p deletion lies within the 9p23 segment, which is supported by the findings of Hauge et al ( 2008 ) and Hou et al ( 2016 ). In the patient reported by Recalcati et al ( 2012 ) and patient 9 of Swinkels et al ( 2008 ), the absence of trigonocephaly in the presence of a deletion >15 Mb may be due to reduced penetrance. Although Swinkels et al ( 2008 ) characterized the critical region of trigonocephaly as a 300 kb segment within 15.1−15.3 Mb from the 9p terminus (9p22.3), according to the range of interstitial deletions in their patients 1−3, the authors did not use BAC clones that covered the region from 8.3 to 14 Mb in these patients.…”

Clinical and molecular delineation of duplication 9p24.3q21.11 in a patient with psychotic behavior

“…3). DOCK8 and KANK1 have been associated with ID (Griggs et al, 2008;Lerer et al, 2005;Recalcati et al, 2012). C9orf66 function remains unknown (Griggs et al, 2008).…”