Delineation of the clinically recognizable 17q22 contiguous gene deletion syndrome in a patient carrying the smallest microdeletion known to date.

ABSTRACT

We describe a patient with a 1.34 Mb microdeletion at chromosome band 17q22, which is also present in his affected mother. To better delineate this microdeletion syndrome, we compare the clinical and molecular characteristics of 10 previously reported cases and our patient. Of these, the present patient has the smallest deletion which includes five genes MMD, TMEM100, PCTP, ANKFN1, and NOG. We compare the clinical manifestations described in relation to NOG, since this is the only gene whose loss is shared by our patient and the other eight patients. Previously, the clinical patterns associated with NOG mutations have been included under the general term "NOG-related symphalangism spectrum disorder (NOG-SSD)." Based on our analyses, and considering that there is a clinical correlation observed in cases with a "17q22 microdeletion including NOG" of which the main characteristics can be contributed to loss of this gene, we propose that the clinical patterns observed in these patients should be named as NOG-spectrum disorder-contiguous gene syndrome (NOGSD-CGS). This designation is important for clinicians because when a patient has defects concordant with alterations of NOG but also presents other anomalies not related to this gene, they would be able to suspect the existence of a microdeletion affecting 17q22, therefore, allowing an early diagnosis. This will also enable the clinician to provide the family with adequate information about the prognosis and the risk of reoccurrence in future potential offspring.