text: <unk>  is the most common subtype of long QT syndrome making up to 55% of all cases of long QT syndrome.  It often presents as a cardiac event that occurs after exercise, and especially during underwater exercise such as swimming or diving.  Homozygous recessive mutations in the gene for<unk>  appear to cause the Jervell and Lange-Nielsen syndrome which is characterized clinically by LQTS and sensorineural deafness. Romano-Ward syndrome is an autosomal dominant form of LQTS that is not associated with deafness.  Events before the age of 10 years old only occur in the<unk>  subtype of LQTS.  Patients with<unk>  paradoxically show a prolongation in the QT segment on EKG after an infusion of epinephrine, which is also used to unmask latent carriers.<unk>  patients are most likely to have the greatest positive response to therapy with beta blockers when compared with the other LQTS subtypes. The mutation occurs on the short arm of chromosome 11.
option_0: LQT1
option_1: LQT2
option_2: LQT3
option_3: LQT4
option_4: LQT5
option_5: LQT6
option_6: LQT8
option_7: LQT9