Defining new guidelines for screening the 22q11.2 deletion based on a clinical and dysmorphologic evaluation of 194 individuals and review of the literature

The 22q11.2 deletion is the most frequent interstitial deletion in humans and presents a wide phenotypic spectrum, with over 180 clinical manifestations described. Distinct studies have detected frequencies of the deletion ranging from 0 % to 75 %, depending on the studied population and selection criteria adopted. Due to the lack of consensus in this matter, several studies have been conducted aiming to define which patients would be eligible for screening; however, the issue is still up for debate. In order to contribute to the delineation of possible clinical and dysmorphologic guidelines to optimize decision making in the clinical setting, 194 individuals with variable features of the 22q11.2 deletion syndromes (22q11.2DS) were evaluated. Group I, clinical suspicion of 22q11.2DS with palatal anomalies; Group II, clinical suspicion without palatal anomalies; Group III, cardiac malformations associated with the 22q11.2DS; and Group IV, juvenile-onset schizophrenia. Multiplex ligation-dependent probe amplification was used for screening the 22q11.2 deletion, which was detected in 45 patients (23.2 %), distributed as such: Group I, 35/101 (34.7 %); Group II, 4/18 (22.2 %); Group III, 6/52 (11.5 %); and Group IV, 0/23 (0 %). Clinical data were analyzed by frequency distribution and statistically. Based on the present results and on the review of the literature, we propose a set of guidelines for screening patients with distinct manifestations of the 22q11.2DS in order to maximize resources. In addition, we report the dysmorphic features which we found to be statistically correlated with the presence of the 22q11.2DS.