Novel frameshift mutation in the KCNQ1 gene responsible for Jervell and Lange-Nielsen syndrome

Jervell and Lange–Nielsen syndrome is an autosomal recessive disorder caused by mutations in KCNQ1 or KCNE1 genes. The disease is characterized by sensorineural hearing loss and long QT syndrome.
Here we present a 3.5-year-old female patient, an offspring of consanguineous marriage, who had a history of recurrent syncope and congenital sensorineural deafness. The patient and the family members were screened for mutations in KCNQ1 gene by linkage analysis and DNA sequencing.
DNA sequencing showed a c.1532_1534delG (p. A512Pfs*81) mutation in the KCNQ1 gene in homozygous form. The results of short tandem repeat (STR) markers showed that the disease in the family is linked to the KCNQ1 gene. The mutation was confirmed in the parents in heterozygous form.
This is the first report of this variant in KCNQ1 gene in an Iranian family. The data of this study could be used for early diagnosis of the condition in the family and genetic counseling.