| A rare multiple congenital anomalies syndrome with cardiac involvement as a major feature with characteristics of QT prolongation, congenital heart defects, syndactyly, facial dysmorphism and neurodevelopmental features. There are three clinical phenotypes; the classical types that present with a prolonged QT interval and either with (Timothy syndrome 1) or without (Timothy syndrome 2) cutaneous syndactyly of fingers and toes. The atypical form (ATS) causes multi-system health concerns but not necessarily with prolonged QT. The disease is due to mutations in the CACNA1C gene (12p13.33). The clinical phenotypes correlate with genotype. Most cases arise de novo however in some cases the disease has been identified as an inherited autosomal dominant trait resulting from parental germline mosaicism. |
