Jervell and Lange-Nielsen syndrome (JLNS) is a rare inherited disorder characterised by congenital deafness and arrhythmia (disruption of the heart's normal rhythm). This condition is a form of long QT syndrome, which is a heart condition that causes the cardiac muscle to take longer than usual to recharge between beats. Since early childhood, these irregular heartbeats increase the risk of syncope and sudden death; however, some individuals remain asymptomatic. Physical activity, excitement or stress may trigger the onset of the symptoms. This disorder affects about 1.6 to 6 per 1 million people worldwide, but in Denmark and Norway, it has a higher prevalence where it affects at least 1 in 200,000 people. JLNS is genetically heterogeneous. JLNS1 is caused by homozygous or compound heterozygous mutations in the KCNQ1 gene and JLNS2 is associated with mutations in KCNE1 gene.
Ardati and Al Saif (1994) described a Bahraini child with Jervell and Lange-Nielsen syndrome (JLNS). Six of the patient's deceased siblings and a surviving cousin were also reported to have been affected by JLNS. The patient had congenital deafness and ECG of both the patient and his cousin displayed prolonged QT interval. Treatment method using propranolol was ineffective for the patient; however, it reduced the frequency of syncope in patient's cousin.
Schulze-Bahr et al. (1997) performed haplotype analysis with microsatellite markers in a Lebanese family with JLNS. The study failed to establish linkage at LQTS1 (potassium-channel gene KVLQT1 ) that is known to cause JLNS and autosomal-dominant long-QT syndrome. It also ruled out two other ion-channel genes associated with autosomal-dominant long-QT syndrome - HERG (LQTS 2) and SCN5A (LQTS 3). Schulze-Bahr et al. (1997) suggested that JLNS could be genetically heterogeneous, and an unknown LQTS gene may be responsible for causing the disease in the Lebanese family.
Adu-Gyamfi et al. (1991) reported a four-year-old girl with deafness who developed polymorphous ventricular tachycardia upon administering anesthesia. Prolonged QTc interval in the post-anesthetic ECG and deafness confirmed Jervell and Lange-Nielsen syndrome. The case report emphasise on the deleterious effects of halothane anesthesia in patients with long QTc interval syndrome.
Al Rakaf et al. (1997) described a two patients from a Saudi family with Jervell and Lange-Nielsen Syndrome. The proband was a 3-year-old girl born to second degree consanguineous parents. She presented with recurrent episodes of seizure and syncope. The proband's brother, who was deaf, died at the age of 3 years following repeated syncopal attack.