Timothy Syndrome is a multiorgan disorder that results from de novo, gain-of-function mutations within the voltage-gated Cav1.2 calcium channel. While G406R mutation occurs within exon 8, G402S and G406R are located in the mutually exclusive exon 8a. All three mutations similarly produced a drastic slowdown of channel inactivation. Excessive Ca2+ currents flowing through the Cav1.2 channels in different tissues underlie pathologies such as arrhythmia, dysregulation of functions in the endocrine and immune systems, autism spectral disorder, and other developmental defects such as syndactyly. Here, we discuss the diverse patterns and regulation of alternative splicing of the Cav1.2 channels, the functional impacts of the TS mutations on channel properties to relate to clinical features, and the possible therapeutic approaches in the future.