LAUSR

CACNA1C encodes the voltage gated L-type calcium channel CaV1.2. A specific gain of function pathogenic variant in CACNA1C causes Timothy syndrome type 1 (TS1) with cardiac long QT syndrome, syndactyly, and neuropsychiatric symptoms. Recent case series highlighted a broader spectrum of CACNA1C-related disorder (CRD) that includes isolated cardiac disease, isolated neurologic deficits, and TS, but it is unknown how the clinical presentation of other CRD variants relate to neural defects. We surveyed individuals with CRD to define the neuropsychiatric and developmental phenotype in an effort to guide future research into the role of calcium channels in neural development. Among 24 participants the most common neuropsychiatric symptoms and/or diagnoses were developmental delay in 92%, incoordination in 71%, hypotonia in 67%, autism spectrum disorder in 50% (autistic features in 92%), seizures in 38%, and attention deficit hyperactivity disorder in 21% of participants. There were no significant differences in symptoms between participants with and without long QT syndrome. These findings indicate the key role of CaV1.2 in brain development and the clinical importance of screening and therapeutically addressing neuropsychiatric symptoms in all individuals with CRD.