# Síndrome QT longo familiar congênito

> Página oficial: https://raras.org/doenca/sindrome-qt-longo-familiar-congenito
> Fonte: Raras.org — Banco de Dados de Doenças Raras em Português (CC BY-NC-SA 4.0)
> Última atualização: 2026-05-07

## Identificadores

- **ORPHA**: 768 — https://www.orpha.net/en/disease/detail/768
- **OMIM**: none — https://omim.org/entry/none

## Descrição clínica

A síndrome de QT Longo congénito (LQTS) é uma doença hereditária cardíaca caracterizada pelo prolongamento do intervalo QT no ECG basal e por um alto risco de arritmias potencialmente fatais.

## Epidemiologia e herança

- **Prevalência**: Unknown
- **Padrão de herança**: Autosomal dominant, Autosomal recessive

## Sinais e sintomas (141 fenótipos HPO)

- **Testa larga** — HPO: HP:0000337
- **Anemia ferropriva** — HPO: HP:0001891
- **Deficiência auditiva neurossensorial profunda** — HPO: HP:0011476
- **Mal-estar pós-esforço** — HPO: HP:0030973
- **Arritmia** — HPO: HP:0011675
- **Perda de consciência** — HPO: HP:0007185
- **Anormalidade do desenvolvimento pré-natal ou nascimento** — HPO: HP:0001197
- **Teste de estresse cardíaco anormal** — HPO: HP:0500018
- **Onda T entalhada** — HPO: HP:0034303
- **Deficiência auditiva** — HPO: HP:0000365
- **Deficiência auditiva neurossensorial bilateral** — HPO: HP:0008619
- **Sindactilia dos dedos 2-3 do pé** — HPO: HP:0004691
- **Ponte nasal ampla** — HPO: HP:0000431
- **Fisiologia anormal do sistema nervoso autônomo** — HPO: HP:0012332
- **Anormalidade da dentição** — HPO: HP:0000164
- **Fraqueza muscular** — HPO: HP:0001324
- **Formato facial anormal** — HPO: HP:0001999
- **Cardiomiopatia dilatada** — HPO: HP:0001644
- **Atraso de crescimento** — HPO: HP:0001510
- **Escafocefalia** — HPO: HP:0030799
- **Anormalidade da cor dentária** — HPO: HP:0011073
- **Onda T anormal** — HPO: HP:0005135
- **Fraqueza flácida episódica** — HPO: HP:0003752
- **Hipoplasia renal** — HPO: HP:0000089
- **Paralisia hipercalêmica periódica** — HPO: HP:0007215
- **Extrassístoles ventriculares polimórficas e politópicas** — HPO: HP:0006696
- **Hiperaldosteronismo** — HPO: HP:0000859
- **Disfunção tubular renal** — HPO: HP:0000124
- **Atraso do neurodesenvolvimento** — HPO: HP:0012758
- **Miocardite** — HPO: HP:0012819
- **Deficiência auditiva neurossensorial congênita** — HPO: HP:0008527
- **Flutter ventricular** — HPO: HP:0011841
- **Sindactilia** — HPO: HP:0001159
- **Imunodeficiência** — HPO: HP:0002721
- **Morte cardíaca súbita abortada** — HPO: HP:0031628
- **Deficiência intelectual** — HPO: HP:0001249
- **Tetralogia de Fallot** — HPO: HP:0001636
- **Atraso global do desenvolvimento** — HPO: HP:0001263
- **Taquicardia ventricular** — HPO: HP:0004756
- **Hipotermia** — HPO: HP:0002045
- _...e mais 101 sintomas. Ver https://raras.org/doenca/sindrome-qt-longo-familiar-congenito._

## Genes associados (21)

- **CALM1** — Calmodulin-1 [Disease-causing germline mutation(s) in]
  - Função: Calmodulin acts as part of a calcium signal transduction pathway by mediating the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding (PubMed:1676
- **ALG10B** — Dol-P-Glc:Glc(2)Man(9)GlcNAc(2)-PP-Dol alpha-1,2-glucosyltransferase B [Candidate gene tested in]
  - Função: Dol-P-Glc:Glc(2)Man(9)GlcNAc(2)-PP-Dol alpha-1,2-glucosyltransferase that operates in the biosynthetic pathway of dolichol-linked oligosaccharides, the glycan precursors employed in protein asparagine
- **TBX5** — T-box transcription factor TBX5 [Candidate gene tested in]
  - Função: DNA-binding protein that regulates the transcription of several genes and is involved in heart development and limb pattern formation (PubMed:25725155, PubMed:25963046, PubMed:26917986, PubMed:2703564
- **NOS1AP** — Carboxyl-terminal PDZ ligand of neuronal nitric oxide synthase protein [Candidate gene tested in]
  - Função: Adapter protein involved in neuronal nitric-oxide (NO) synthesis regulation via its association with nNOS/NOS1. The complex formed with NOS1 and synapsins is necessary for specific NO and synapsin fun
- **TRDN** — Triadin [Candidate gene tested in]
  - Função: Contributes to the regulation of lumenal Ca2+ release via the sarcoplasmic reticulum calcium release channels RYR1 and RYR2, a key step in triggering skeletal and heart muscle contraction. Required fo
- **SCN10A** — Sodium channel protein type 10 subunit alpha [Candidate gene tested in]
  - Função: Tetrodotoxin-resistant channel that mediates the voltage-dependent sodium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across
- **KCNH2** — Voltage-gated inwardly rectifying potassium channel KCNH2 [Disease-causing germline mutation(s) in]
  - Função: Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel (PubMed:10219239, PubMed:10753933, PubMed:10790218, PubMed:10837251, PubMed:11997281, PubMed:12063277, PubMed:185594
- **KCNJ5** — G protein-activated inward rectifier potassium channel 4 [Disease-causing germline mutation(s) in]
  - Função: Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration o
- **AKAP9** — A-kinase anchor protein 9 [Disease-causing germline mutation(s) in]
  - Função: Scaffolding protein that assembles several protein kinases and phosphatases on the centrosome and Golgi apparatus. Required to maintain the integrity of the Golgi apparatus (PubMed:10202149, PubMed:15
- **KCNJ2** — Inward rectifier potassium channel 2 [Disease-causing germline mutation(s) in]
  - Função: Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it (PubMed:36149965, PubMed:7590287, PubMed:9490857). Their volt
- **KCNE2** — Potassium voltage-gated channel subfamily E member 2 [Disease-causing germline mutation(s) in]
  - Função: Ancillary protein that functions as a regulatory subunit of the voltage-gated potassium (Kv) channel complex composed of pore-forming and potassium-conducting alpha subunits and of regulatory beta sub
- **SCN5A** — Sodium channel protein type 5 subunit alpha [Disease-causing germline mutation(s) in]
  - Função: Pore-forming subunit of Nav1.5, a voltage-gated sodium (Nav) channel that directly mediates the depolarizing phase of action potentials in excitable membranes. Navs, also called VGSCs (voltage-gated s
- **CALM2** — Calmodulin-2 [Disease-causing germline mutation(s) in]
  - Função: Calmodulin acts as part of a calcium signal transduction pathway by mediating the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding (PubMed:1676
- **CACNA1C** — Voltage-dependent L-type calcium channel subunit alpha-1C [Disease-causing germline mutation(s) in]
  - Função: Pore-forming, alpha-1C subunit of the voltage-gated calcium channel that gives rise to L-type calcium currents (PubMed:12181424, PubMed:15454078, PubMed:15863612, PubMed:16299511, PubMed:17224476, Pub
- **CAV3** — Caveolin-3 [Disease-causing germline mutation(s) in]
  - Função: May act as a scaffolding protein within caveolar membranes. Interacts directly with G-protein alpha subunits and can functionally regulate their activity. May also regulate voltage-gated potassium cha

## Medicamentos em desenvolvimento (5)

- RANOLAZINE — Fase Phase 2 (Sodium channel protein type V alpha subunit blocker)
- IVACAFTOR — Fase Phase 2 (Cystic fibrosis transmembrane conductance regulator positive modulator)
- LUMACAFTOR — Fase Phase 2 (Cystic fibrosis transmembrane conductance regulator stabiliser)
- PRINABEREL — Fase Phase 1 (Estrogen receptor beta agonist)
- DOFETILIDE — Fase Phase 1 (HERG blocker)
- Fonte: https://platform.opentargets.org/disease/MONDO_0019171

## Ensaios clínicos ativos (8)

- **NCT05964322** [COMPLETED]: Cardiac Rehabilitation of Children and Adolescent With Long QT Syndrome — https://clinicaltrials.gov/study/NCT05964322
- **NCT05906732** [TERMINATED]: Study of LQT-1213 on QTc-induced Prolongation in Healthy Adult Subjects (Part1) and on Congenital Long QT in Patients Diagnosed With Type 2 or 3 Long QT Syndrome (Part 2). — https://clinicaltrials.gov/study/NCT05906732
- **NCT04328376** [COMPLETED]: Measurement of the Electromechanical Window to Improve the Diagnosis of Congenital Long QT Syndrome — https://clinicaltrials.gov/study/NCT04328376
- **NCT04728100** [COMPLETED]: LQT and Smartphone/Smartwatch — https://clinicaltrials.gov/study/NCT04728100
- **NCT05759962** [COMPLETED]: Phase 1 Study of LQT-1213 in Healthy Adults — https://clinicaltrials.gov/study/NCT05759962
- **NCT03544918** [COMPLETED]: Prevalence of Congenital Long QT Syndrome and Acquired QT Prolongation in a Hospital Cohort — https://clinicaltrials.gov/study/NCT03544918
- **NCT02680080** [COMPLETED]: Effect of Grapefruit on QT Interval in Healthy Volunteers and Patients With Congenital Long QT Syndrome — https://clinicaltrials.gov/study/NCT02680080
- **NCT01728025** [UNKNOWN]: Long Term Prophylactic Therapy of Congenital Long QT Syndrome Type III (LQT3) With Ranolazine — https://clinicaltrials.gov/study/NCT01728025

## Centros de referência no Brasil (24)

- Hospital Universitário Prof. Edgard Santos (HUPES) (Salvador/BA)
- Hospital Infantil Albert Sabin (Fortaleza/CE)
- Hospital de Apoio de Brasília (HAB) (Brasília/DF)
- Hospital Estadual Infantil e Maternidade Alzir Bernardino Alves (HIABA) (Vila Velha/ES)
- Hospital das Clínicas da UFG (Goiânia/GO)
- Hospital Universitário da UFJF (Juiz de Fora/MG)
- Hospital das Clínicas da UFMG (Belo Horizonte/MG)
- Hospital Universitário Julio Müller (HUJM) (Cuiabá/MT)
- Hospital Universitário João de Barros Barreto (Belém/PA)
- Hospital Universitário Lauro Wanderley (HULW) (João Pessoa/PB)
- Instituto de Medicina Integral Prof. Fernando Figueira (IMIP) (Recife/PE)
- Hospital Pequeno Príncipe (Curitiba/PR)
- Hospital Universitário Regional de Maringá (HUM) (Maringá/PR)
- Hospital de Clínicas da UFPR (Curitiba/PR)
- Hospital Universitário Pedro Ernesto (HUPE-UERJ) (Rio de Janeiro/RJ)
- Instituto Nacional de Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira (IFF/Fiocruz) (Rio de Janeiro/RJ)
- Hospital São Lucas da PUCRS (Porto Alegre/RS)
- Hospital de Clínicas de Porto Alegre (HCPA) (Porto Alegre/RS)
- Hospital Universitário da UFSC (HU-UFSC) (Florianópolis/SC)
- Hospital das Clínicas da FMUSP (São Paulo/SP)

## Doenças relacionadas (por similaridade fenotípica)

- [Síndrome do QT longo de Romano-Ward](https://raras.org/doenca/sindrome-do-qt-longo-de-romano-ward) — ORPHA:101016 — 141 sintomas em comum
- [Paralisia periódica genética](https://raras.org/doenca/paralisia-periodica-genetica) — ORPHA:371433 — 82 sintomas em comum
- [Paralisia periódica](https://raras.org/doenca/paralisia-periodica) — ORPHA:206976 — 82 sintomas em comum
- [Síndrome Andersen-Tawil](https://raras.org/doenca/sindrome-andersen-tawil) — ORPHA:37553 — 76 sintomas em comum
- [Monossomia parcial do braço longo do cromossomo 14](https://raras.org/doenca/monossomia-parcial-do-braco-longo-do-cromossomo-14) — ORPHA:262110 — 34 sintomas em comum
- [Síndrome de blefarofimose-perturbação do desenvolvimento intelectual](https://raras.org/doenca/sindrome-de-blefarofimose-perturbacao-do-desenvolvimento-intelectual) — ORPHA:293642 — 33 sintomas em comum
- [Monossomia parcial do cromossomo 19](https://raras.org/doenca/monossomia-parcial-do-cromossomo-19) — ORPHA:261841 — 32 sintomas em comum
- [Monossomia parcial do cromossomo 3](https://raras.org/doenca/monossomia-parcial-do-cromossomo-3) — ORPHA:261776 — 32 sintomas em comum
- [Síndrome Dubowitz](https://raras.org/doenca/sindrome-dubowitz) — ORPHA:235 — 32 sintomas em comum
- [Monossomia parcial do braço longo do cromossomo 1](https://raras.org/doenca/monossomia-parcial-do-braco-longo-do-cromossomo-1) — ORPHA:262001 — 32 sintomas em comum

## Importante

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Pacientes devem consultar profissionais de saúde qualificados para decisões clínicas.

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