<unk>  is a rare autosomal recessive condition that leads to sensorineural deafness, abnormal ventricular myocardial repolarization which results in long QT<unk>  (LQTS) and other cardiac events.<unk>  is due to KCNQ1 or KCNE1 gene mutations. The<unk>  of symptoms and severity of symptoms in<unk>  differs from patient to patient. In The United States of America in order to categorise a condition as a rare disease it should affect fewer than 200,000 people. Rare diseases also called as orphan diseases. Orphan Drug Act was passed on 1983 by congress for the rare diseases. Today an average of 25-30 million americans have been reported with rare diseases. The number of people with individual rare disease may be less but overall the number of people with rare diseases are<unk>  in number.
Jervell and Lange-Nielsen syndrome
Laron syndrome
Cruveilhier-Baumgarten syndrome
Fox-Fordyce disease
Cowden syndrome
Melkersson-Rosenthal syndrome
Turcot syndrome
Sturge-Weber syndrome