De novo 393 kb microdeletion of 7p11.2 characterized by aCGH in a boy with psychomotor retardation and dysmorphic features

Abstract

We report on a 27 month old boy presenting with psychomotor delay and dysmorphic features, mainly mild facial asymmetry, prominent cup-shaped ears, long eyelashes, open mouth appearance and slight abnormalities of the hands and feet. Array comparative genomic hybridization revealed a 393 kb microdeletion in 7p11.2. We discuss the possible involvement of CHCHD2, GBAS, MRPS17, SEPT14 and PSPH on our patient's phenotype. Additionally, we studied the expression of two other genes deleted in the patient, CCT6A and SUMF2, for which there is scarce data in the literature. Based on current knowledge and the de novo occurrence of this finding in our proband we presume that the aberration is likely to be pathogenic in our case. However, a single gene disorder, elsewhere in the genome or in this very region cannot be ruled out. Further elucidation of the properties of this chromosomal region, as well as of the role of the genes involved will be needed in order to draw safe conclusions regarding the association of the chromosomal deletion with the patient's features.

Keywords: CCT6A; CHCHD2; Deletion 7p11.2; Dysmorphic features; GBAS; MRPS17; PSPH; Psychomotor delay; SEPT14; SUMF2.

Fig. 1

FISH analysis for the confirmation of the observed deletion. Whole chromosome 7 paint probe WCP7 (red) and BAC probe RP11-769B4 (green) were used. Notice the absence of the RP11-769B4 probe in the patient's chromosome (arrowhead) but not in the parental chromosomes.

Fig. 2

Quantitative RT-PCR analysis of CCT6A and SUMF2 for patient's family members. The graph shows the median ratios of triplicate experiments for CCT6A and SUMF2 mRNA levels, divided by the GAPDH mRNA levels.

Fig. 3

Schematic view of the 393 kb deletion region in this case and other reported cases. Information for the patient reported by Coulter et al. (2011) and the case in the DECIPHER database (https://decipher.sanger.ac.uk/) (patient 255179), the ISCA database (https://www.iscaconsortium.org/index.php/search) (patients nssv584505, nssv582021) as well as the Database of Genomic Variants (http://projects.tcag.ca/variation/) (patients esv2734447, dgv1201e199) are also included.