Roux-Buisson et al. (2012) studied 2 families with cardiac arrhythmias. In the first family, which originated from the French West Indies, the 2-year-old proband experienced syncope followed by cardiac arrest after a shock while playing with his 7-year-old ... Roux-Buisson et al. (2012) studied 2 families with cardiac arrhythmias. In the first family, which originated from the French West Indies, the 2-year-old proband experienced syncope followed by cardiac arrest after a shock while playing with his 7-year-old brother. Resting electrocardiogram (ECG) after resuscitation showed numerous polymorphic or bidirectional ventricular extra beats and runs of polymorphic ventricular tachycardia. The proband died in the hospital 3 weeks after the initial cardiac arrest, following a severe postanoxic coma. His parents and brother were unaffected, with normal ECGs, Holter recordings, and exercise stress tests. The proband of the second family, which originated from western France, was a 26-year-old man who had recurrent exercise-induced syncope since infancy. Resting ECG was normal with no prolongation of the QT interval, but exercise testing showed numerous bidirectional ventricular extra beats. In addition, he had proximal muscle weakness. Examination of his dizygotic twin brother revealed that he also had catecholaminergic polymorphic ventricular tachycardia. Other family members had no abnormalities on clinical evaluation, Holter recording, and exercise testing.
In a cohort of 97 patients with CPVT in whom mutations in the RYR2 (180902) and CASQ2 (114251) genes had been excluded, Roux-Buisson et al. (2012) analyzed the candidate genes TRDN and ASPH (600582) and identified homozygosity for ... In a cohort of 97 patients with CPVT in whom mutations in the RYR2 (180902) and CASQ2 (114251) genes had been excluded, Roux-Buisson et al. (2012) analyzed the candidate genes TRDN and ASPH (600582) and identified homozygosity for a frameshift mutation in the TRDN gene (603283.0001) in a family from the French West Indies, and compound heterozygosity for a missense (T59R; 603283.0002) and a nonsense (Q205X; 603283.0003) TRDN mutation in a French family. No mutations were identified in the ASPH gene, and the TRDN mutations segregated with disease in each family. Roux-Buisson et al. (2012) noted that all 3 TRDN mutations were located in a region of the gene common to all triadin isoforms, including skeletal muscle isoforms.