Rabbit Anti-Human CACNB2 (internal) Polyclonal antibody

Autism Spectrum Disorders (ASD) are complex neurodevelopmental diseases clinically defined by dysfunction of social interaction. Dysregulation of cellular calcium homeostasis might be involved in ASD pathogenesis, and genes coding for the L-type calcium channel subunits Ca(V)1.2 (CACNA1C) and Ca-V beta 2 (CACNB2) were recently identified as risk loci for psychiatric diseases. Here, we present three rare missense mutations of CACNB2 (G167S, S197F, and F240L) found in ASD-affected families, two of them described here for the first time (G167S and F240L). All these mutations affect highly conserved regions while being absent in a sample of ethnically matched controls. We suggest the mutations to be of physiological relevance since they modulate whole-cell Ba2+ currents through calcium channels when expressed in a recombinant system (HEK-293 cells). Two mutations displayed significantly decelerated time-dependent inactivation as well as increased sensitivity of voltage-dependent inactivation. In contrast, the third mutation (F240L) showed significantly accelerated time-dependent inactivation. By altering the kinetic parameters, the mutations are reminiscent of the CACNA1C mutation causing Timothy Syndrome, a Mendelian disease presenting with ASD. In conclusion, the results of our first-time biophysical characterization of these three rare CACNB2 missense mutations identified in ASD patients support the hypothesis that calcium channel dysfunction may contribute to autism.

Hypertrophic cardiomyopathy (HCM) is a highly heterogeneous disease displaying considerable interfamilial and intrafamilial phenotypic variation, including disease severity, age of onset, and disease progression. This poorly understood variance raises the possibility of genetic modifier effects, particularly in MYBPC3-associated HCM. In a large consanguineous Chinese HCM family, we identified 8 members harboring the MYBPC3 c.3624delC (p.Lys1209Serfs) disease-causing mutation, but with very disparate phenotypes. Genotyping ruled out the modifying effect of previously described variants in renin-angiotensin-aldosterone system. Afterwards, we screened for modifying variants in all known causing genes and closely related genes for cardiomyopathy and channelopathy by performing targeted next-generation sequencing. For first time, we showed that a c.1598C>T (p.Ser533Leu) mutation in voltage-dependent l-type calcium channel subunit beta-2 (CACNB2) was present in all severely affected HCM patients, but not in those moderately affected or genotype-positive phenotype-negative patients. This CACNB2 p.Ser533Leu mutation is extremely conserved in evolution, and was not found in 550 healthy controls. Our results suggest that CACNB2 is a possible candidate genetic modifier of MYBPC3-associated familial HCM, but more genetic evidence and functional experiments are needed to confirm.