There are minimal data on the impact of genetic counselors in subspecialty clinics, including the pediatric arrhythmia clinic. This study aimed to describe the clinical encounters of a genetic counselor integrated into a pediatric arrhythmia clinic. In the 20 months between July 2015 and February 2017, a total of 1914 scheduled patients were screened for indications relevant for assessment by a genetic counselor. Of these, the genetic counselor completed 276 patient encounters, seeing 14.4% of all patients in clinic. The most expected and common indications for genetic counselor involvement were related to suspicion for primary heritable arrhythmia conditions, though patients seen in this clinic display a wide range of cardiac problems and many additional indications for genetic evaluation were identified. Roughly 75% (211/276) of encounters were for personal history of confirmed/suspected heritable disease, including cardiac channelopathies, cardiomyopathies, ventricular arrhythmias, and congenital heart defects, and 25% (65/276) were for family history of disease, including long QT syndrome and sudden unexplained death. Overall, this study shows that about 1 in 7 patients seen in a pediatric arrhythmia clinic have indications that likely benefit from genetic counselor involvement and care. Similar service delivery models embedding genetic counselors in pediatric arrhythmia clinics should be encouraged, and this model could be emulated to increase patient access to genetic counseling services.

3531 Background: Previously reported results of this randomized study demonstrated that the addition of dalotuzumab (Dz) worsened the PFS and OS of chemofractory mCRC patients receiving Cx and Ir (Watkins et al; ASCO 2011). Comprehensive molecular analysis has been undertaken retrospectively to identify possible predictors of Cx resistance and Dz response. Methods: Quantitative RT-PCR for IGF-1, IGF-2, immunohistochemistry for IGF-1R and microarray expression profiling was conducted on archival tumor tissue. All patients had received Cx and Ir with either placebo (n=107), weekly Dz (n=112), or 2 weekly Dz (n=110). Results: Data from 292 and 206 patients was successfully obtained by RT-PCR or microarray respectively. Within the placebo arm, high IGF-1 expression was found to be associated with resistance to Cx (IGF-1-/IGF-1+; PFS 6.7/3.7 months, OS 15.5/9.6 months). High IGF-1 expression was associated with benefit from the addition of weekly Dz (placebo/weekly Dz; PFS 3.7/5.7 months, OS 9.6/18.2 months). By contrast the addition of Dz was not effective in tumors with high IGF-2 expression (placebo/weekly Dz; PFS 8.4/2.7 months). Microarray analysis revealed distinct populations that differentially correlated with Cx and Dz response. An epithelial phenotype appeared more associated with Cx response, whereas a mesenchymal phenotype more associated with Dz response. Rectal cancers showed greater association with increased IGF-1 expression, EMT gene signature and Dz response. Conclusions: These data support IGF-1 and IGF-2 as potential biomarkers for response to Dz therapy and high IGF-1 as a marker of resistance to Cx therapy. Based on these data Dz is being further evaluated in a molecularly selected population of mCRC. [Table: see text]

Introduction:The SCN5A gene is implicated in many arrhythmogenic and cardiomyopathic processes. We identified a novel SCN5A variant in a family with significant segregation in individuals affected with progressive sinus and atrioventricular nodal disease, atrial arrhythmia, dilated cardiomyopathy, and early sudden cardiac arrest.Methods:A patient pedigree was created following the clinical evaluation of three affected individuals, two monozygotic twins and a paternal half-brother, which lead to the evaluation of a paternal half-sister (four siblings with the same father and three mothers) all of whom experienced varying degrees of atrial arrhythmias, conduction disease, and dilated cardiomyopathy in addition to a paternal history of unexplained death in his 50s with similar autopsy findings. The index male underwent sequencing of 58 genes associated with cardiomyopathies. Sanger sequencing was used to provide data for bases with insufficient coverage and for bases in some known regions of genomic segmental duplications. All clinically significant and novel variants were confirmed by independent Sanger sequencing.Results:All relatives tested were shown to have the same SCN5A variant of unknown significance (p. Asp197His) and the monozygotic twins shared a co-occurring NEXN (p. Glu575*). Segregation analysis demonstrates likely pathogenic trait for the SCN5A variant with an additional possible role for the NEXN variant in combination.Conclusions:There is compelling clinical evidence suggesting that the SCN5A variant p. Asp197His may be re-classified as likely pathogenic based on the segregation analysis of our family of interest. Molecular mechanism studies are pending.