Diseases of the circulatory system
Other forms of heart disease
Autosomal dominant
11p15.5-p15.4
Long QT Syndrome is a cardiac disorder, characterized by a delay of the cardiac muscles in recharging the electrical stimulus between beats. This leads to a prolonged interval between two consecutive beats, referred to as the QT interval. While a prolonged QT interval is not harmful per se, it can result in arrhythmia, which may lead to cardiac arrests, and sudden death. LQTS1 is caused by heterozygous mutations in the KCNQ1 gene, which encodes a voltage-gated potassium channel.
| Subject ID | Country | Sex | Family History | Parental Consanguinity | HPO Terms | Variant | Zygosity | Mode of Inheritance | Reference | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|
| 192500.1.1 | Saudi Arabia | Male | Yes | Yes | Syncope; Prolonged QTc interval Syncope; Prolonged QTc interval  | NM_000218.2:c.387-5T>A | Heterozygous | Autosomal, Dominant | Bhuiyan et al. 2009 | |
| 192500.1.2 | Saudi Arabia | Male | Yes | | NM_000218.2:c.387-5T>A | Heterozygous | Autosomal, Dominant | Bhuiyan et al. 2009 | Father of 192500.1.1 | |
| 192500.1.3 | Saudi Arabia | Female | Yes | | NM_000218.2:c.387-5T>A | Heterozygous | Autosomal, Dominant | Bhuiyan et al. 2009 | Mother of 192500.1.1 | |
| 192500.2.1 | Saudi Arabia | Male | No | Yes | Generalized-onset seizure; Cyanotic epi... Generalized-onset seizure; Cyanotic episode; Prolonged QTc interval | NM_000218.2:c.387-5T>A | Heterozygous | Autosomal, Dominant | Bhuiyan et al. 2009 | |
| 192500.3.01 | Saudi Arabia | Female | Yes | No | Syncope; Prolonged QTc interval Syncope; Prolonged QTc interval | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | |
| 192500.3.02 | Saudi Arabia | Female | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Mother of 192500.3.0... |
| 192500.3.03 | Saudi Arabia | Female | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Daughter of 192500.3... |
| 192500.3.04 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Brother of 192500.3.... |
| 192500.3.05 | Saudi Arabia | Male | Yes | No | Syncope; Prolonged QTc interval Syncope; Prolonged QTc interval | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Brother of 192500.3.... |
| 192500.3.06 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Brother of 192500.3.... |
| 192500.3.07 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Nephew of 192500.3.0... |
| 192500.3.08 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Nephew of 192500.3.0... |
| 192500.3.09 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Nephew of 192500.3.0... |
| 192500.3.10 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Nephew of 192500.3.0... |
| 192500.3.11 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Nephew of 192500.3.0... |
| 192500.3.12 | Saudi Arabia | Male | Yes | No | | NM_000218.2:c.773A>C | Heterozygous | Autosomal, Dominant | Shinwari et al. 2013 | Nephew of 192500.3.0... |
| 192500.4 | Lebanon | Female | No | Torsade de pointes; Syncope; Anemia; Dee... Torsade de pointes; Syncope; Anemia; Deep venous thrombosis; Type II diabetes mellitus | NM_000218.3:c.1591C>T, NM_000238.4:c.967G>A | Heterozygous | Refaat et al. 2016 | Patient has long-sta... | ||
| 192500.G.1 | Tunisia | Unknown | Prolonged QTc interval Prolonged QTc interval | NM_000335.4:c.5366A>G | Heterozygous | Autosomal, Dominant | Benhorin et al. 1998 | Group of 23 family m... |
Vurgese et al. (2006) described a 35-year old Arab patient with a rare diagnosis of Guillain Barre syndrome in comorbidity with Romano Ward syndrome.
[Vurgese T, Mapkar OA, Surrun SK. Guillain-Barre syndrome in a patient with Romano-Ward syndrome: a case report. Kuwait Med J. 2006; 38(1):53-5.]
Schulze-Bahr et al. (1997) performed haplotype analysis in a Lebanese family with Jervell Lange-Nielsen syndrome, but failed to detect linkage at LQTS 1. Using this approach, they also excluded two other ion-channel genes involved in autosomal-dominant LQTS, HERG (LQTS2) and SCN5A (LQTS3).
Subramanyan and Venugopalan (2002) reported a consanguineous family with a malignant form of long QT syndrome that resulted in the deaths of four children.
Gorgels et al. (1998) described a 2-year old boy who was diagnosed with a rare condition of LQTS with impaired AV conduction.
Benhorin et al. (1993) referred to the unpublished work of Kerem and colleagues who indicated the existence of more than one genetic form of LQT and excluded linkage with HRAS1 in a very large affected Jewish family originating from the island of Jerba near Tunis.