Abstract:

Background: Myotonia Congenita (MC) is a hereditary neuromuscular disorder caused by a mutation in chloride voltage-gated channel 1 (CLCN1) gene. The incidence of MC is estimated as 1 in 100.000. The absence of left main coronary artery (LMCA) anomaly is a rare coronary anomaly. Here we present a family with four members who have MC variation carrier and cardiovascular risk. Materials and Methods: The demographic features, laboratory findings, anthropometric measurements and cardiological examination of the cases were recorded. In addition, CLCN1 gene was sequenced by NGS and possible causes of inherited thrombophilia risk including MTHFR (A1298C), Factor V Leiden (G1691A), Factor II (G20210A), MTHFR (C677T), Factor V Cambridge (G1091C), plasminogen activator inhibitor 1 (PAI-1) 4G/5G, APOE, APOB, ITGB, ACE (ins/del), FVHR2 and FGB gene alterations were evaluated. Results: Case 1 had homozygous c.1886T>C(p.Leu629Pro) alteration in CLCN1 gene and also coronary artery disease, myocardial infarction (MI) history, hyperlipidemia, primary hypertension, vertigo, Lomber disc herniation and hearing loss. LMCA was not detected in coronary angiography in case 1. The other cases (2, 3 and 4) have heterozygous c.1886T>C (p.Leu629Pro) alteration with normal electrocardiographic and echocardiographic findings. Additionally, all of family members had genetic risk factors for the related gene, which lead to an increased risk of cardiovascular disease. Conclusions: Due to alteration of chloride channels in cardiomyocytes leads to variable myocardial involvement, cases with MC should be regularly followed for cardiovascular risk. Moreover, the cases with MC and with genetic profile associated with high cardiovascular risk should also be regularly followed up by cardiologists.

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