Short QT syndrome classification
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Five variants of short QT syndrome have been characterized based upon the underlying genetic mutation, the electrocardiographic phenotype, and the clinical manifestations of the variant.
Short QT syndrome type 1 (SQT1)
Short QT syndrome type 2 (SQT2)
Short QT syndrome type 3 (SQT3)
This variant results from a G514A substitution in the KCNJ2 gene ( a change from aspartic acid to asparagine at position 172 (D172N))[1]. This causes a defect in the gene coding for the inwardly rectifying Kir2.1 (I(K1)) channel. The ECG shows asymmetrical T waves. These patients have an increased risk for re-entry arrhythmias.
Short QT syndrome type 4 (SQT4)
A loss of function mutation in the CACNA1C gene alters the encoding for the α1- and β2b-subunits of the L-type calcium channel. The phenotype is similar to Brugada syndrome combined with a short QT interval. There is an increased risk of sudden cardiac death.
Short QT syndrome type 5 (SQT5)
A loss of function mutation in the CACNB2B gene alters the encoding for the α1- and β2b-subunits of the L-type calcium channel. The phenotype is similar to Brugada syndrome combined with a short QT interval. There is an increased risk of sudden cardiac death.
References
- ↑ Priori SG, Pandit SV, Rivolta I, Berenfeld O, Ronchetti E, Dhamoon A, Napolitano C, Anumonwo J, di Barletta MR, Gudapakkam S, Bosi G, Stramba-Badiale M, Jalife J (2005). "A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene". Circulation Research. 96 (7): 800–7. doi:10.1161/01.RES.0000162101.76263.8c. PMID 15761194. Retrieved 2012-09-02. Unknown parameter
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