{"frequencyBands":{"HP:0040280":[100,100],"HP:0040281":[80,99],"HP:0040282":[30,79],"HP:0040283":[5,29],"HP:0040284":[1,4],"HP:0040285":[0,0]},"page":{"columns":[{"gene":"","key":"MONDO:0012312/OMIM:609620","label":"Short QT syndrome 1","mondoId":"MONDO:0012312","onsetQualifier":null,"recordKeys":["0416e352026749bd96a8469b0b71813098e7bf03973f4612d3a7e1084d8df2f6","2eea1e03908d3d4442b949c94d4ad6ddf5d4062719526b516617bf573e377fe3","929dcbc60a277291bacebaefb503dd563d87279dc441d96aa79e02cea4b17303","d4477712b5b26c421d533508e5d8f8cbcdbe1c4d4e1b42f76732561efa765942","f1499ebbbd1d889df230837dcc42bf833f4e74373ccb69e49513392669c87ad1","ff71ccc0688736ca27632ddfabc79622f24176c9b335c0979236e43160b55172"],"recordQualifiers":{},"scopeLabel":"OMIM:609620","sourceIds":["OMIM:609620"],"sourceScope":"This column retains the native source entry. It is not a pooled estimate for the umbrella condition."},{"gene":"","key":"MONDO:0012313/OMIM:609621","label":"Short QT syndrome 2","mondoId":"MONDO:0012313","onsetQualifier":null,"recordKeys":["18ecc2997266b542f1c3539b86596015dfc8ad8054af9215193f9f82e68d92b4","1e2b9a5b09645d9b0d23453bcfbd6718e088fffa14219fdcab20540b607343d3","3cfb1ed8216b4807b50940f06d744815ab4a0d0d547dc4344ac7a0195b86c216","5bfd884274fba8e9d859a8aacf984c09f0521a725d1c271b57792f2da7160b3d","7a0a74e6c5072e2474c952f07668335002873f6d194413ee4f6c01facd7b317f","e4a4484dcad679810f4aa287ddf4b67dbc1150e609986a1c44b75497d586a536"],"recordQualifiers":{},"scopeLabel":"OMIM:609621","sourceIds":["OMIM:609621"],"sourceScope":"This column retains the native source entry. It is not a pooled estimate for the umbrella condition."},{"gene":"","key":"MONDO:0012314/OMIM:609622","label":"Short QT syndrome 3","mondoId":"MONDO:0012314","onsetQualifier":null,"recordKeys":["1d48e05d706416b0167adbc3c13bff3137821e01969abfcdfe49dcfa54318938","2200bab2980c98a09c5bb0d30334070b6eec3e9597c6490f723891ab78fd4ed1","7720fde7a428c2df7c0b5a01e4f9dbd6bb60eb3612c06de5713accecf733022c","9ce1ef0050d3a729f39889e5a2104fb0ff8ca654c39e0312ffc01bda8a0312ca","b547719f70651450caf86aae11ca5f4af7faac1584226beb9bdc252db0345476","f3aa6f1a6dcc99845324fdb9270ba2364f80c007f3994819859d607513048abc"],"recordQualifiers":{},"scopeLabel":"OMIM:609622","sourceIds":["OMIM:609622"],"sourceScope":"This column retains the native source entry. It is not a pooled estimate for the umbrella condition."},{"gene":"","key":"MONDO:0859368/OMIM:620231","label":"Short QT syndrome 7","mondoId":"MONDO:0859368","onsetQualifier":null,"recordKeys":["26cbfbca255b3a0b4d498d289385bb53efa1ac50062bd1cb206b6707c1529aed","749edd2760f2e85e4ab30b07fdd6e63bdeb84ba313b0c5af0bb0cc94c015baf8","7fec013ad3e3197e162153edb0d31fc2bd8f64b12709ea41b20d90237284df7e","a14ea5eb2615ce1140d040f2f4299f60d0d4160be3fe042beb3ee1873b81f65f","c1d7830688cd9e54a7204a6005f0bdcf5aa88c3467fffad70280ed5c468b5f42"],"recordQualifiers":{},"scopeLabel":"OMIM:620231","sourceIds":["OMIM:620231"],"sourceScope":"This column retains the native source entry. It is not a pooled estimate for the umbrella condition."},{"gene":"","key":"MONDO:0000453/ORPHA:51083","label":"Congenital short QT syndrome","mondoId":"MONDO:0000453","onsetQualifier":null,"recordKeys":["14f56406127ee97c4f03c9595f08795f36aa6570a39c1333928233314f11f722","687ab8e718dbb8f5a019a8a61060d6285edff622ec7adefcc0f42399ab75ef8e","6f619f007ec2e90abe6eca23f9c15e40a32fa3d704746818d6fef05b8db8c413","793236acb23468492c562db141c67258215deee226762ac22433fe56fe0372a3","991aee72fc6b0896dab06b23e41d2257f65f547c97b508ca35167cb91bbfc570","ac92dea5edd44dc5d67c9c95af5792edf8a044249911082a23ede0f7d22fe27c","b705474e695614912aabda3bcb4f697333132e0c62e29de8f30f718ce84a421a","b7ae630e536713574a48a0aa71a7d9f0bb0d60ac5d0d58523f89befbc81e5b2e","ef135bad1c8751ea912ba1c2e0ee3ef01184174e2e61eca8d3168b69e4c6fa9a"],"recordQualifiers":{},"scopeLabel":"ORPHA:51083","sourceIds":["ORPHA:51083"],"sourceScope":"This column retains the native source entry. It is not a pooled estimate for the umbrella condition."}],"comparison":{"collapseColumnsLabel":"Show initial comparisons","defaultColumnKeys":["MONDO:0012312/OMIM:609620","MONDO:0012313/OMIM:609621","MONDO:0012314/OMIM:609622","MONDO:0859368/OMIM:620231"],"expandColumnsLabel":"Compare all source entries","intro":"Compare the original source entries. Different entries may describe different patient groups.","primaryFeatureIds":[],"scopeNoteHtml":"<p>Each column keeps its native condition scope. Initial features are displayed alphabetically, not ranked by clinical importance. Counts remain separate, and an empty cell does not mean a feature cannot occur.</p>"},"coverage":{"countRecords":6,"emptyColumnKeys":[],"hpoRelease":"2026-06-23","narrativeSourceChanges":[],"records":32,"sourceGroups":{"omim":2,"orphanet":9,"published":21}},"features":[{"hpoId":"HP:0005110","label":"Atrial fibrillation","primary":false},{"hpoId":"HP:0001678","label":"Atrioventricular block","primary":false},{"hpoId":"HP:0001662","label":"Bradycardia","primary":false},{"hpoId":"HP:0001695","label":"Cardiac arrest","primary":false},{"hpoId":"HP:0012663","label":"Mildly reduced left ventricular ejection fraction","primary":false},{"hpoId":"HP:0001962","label":"Palpitations","primary":false},{"hpoId":"HP:0004757","label":"Paroxysmal atrial fibrillation","primary":false},{"hpoId":"HP:0031972","label":"Presyncope","primary":false},{"hpoId":"HP:0012232","label":"Shortened QT interval","primary":false},{"hpoId":"HP:0001645","label":"Sudden cardiac death","primary":false},{"hpoId":"HP:0001279","label":"Syncope","primary":false},{"hpoId":"HP:0004308","label":"Ventricular arrhythmia","primary":false},{"hpoId":"HP:0001663","label":"Ventricular fibrillation","primary":false}],"ledeHtml":"Short QT syndrome is a condition that can cause a disruption of the heart&#x27;s normal rhythm (arrhythmia). In people with this condition, the heart (cardiac) muscle takes less time than usual to recharge between beats. The term &quot;short QT&quot; refers to a specific pattern of heart activity that is detected with an electrocardiogram (EKG), which is a test used to measure the electrical activity of the heart. In people with this condition, the part of the heartbeat known as the QT interval is abnormally short.","mondoId":"MONDO:0000453","records":[{"frequencyKind":"reported","key":"0416e352026749bd96a8469b0b71813098e7bf03973f4612d3a7e1084d8df2f6","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609620","disease_name":"Short QT syndrome 1","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001695","is_excluded":false,"label":"Cardiac arrest","onset_id":null,"reference":"PMID:14676148","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"14f56406127ee97c4f03c9595f08795f36aa6570a39c1333928233314f11f722","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040280","hpo_id":"HP:0012232","is_excluded":false,"label":"Shortened QT interval","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"18ecc2997266b542f1c3539b86596015dfc8ad8054af9215193f9f82e68d92b4","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609621","disease_name":"Short QT syndrome 2","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0001663","is_excluded":false,"label":"Ventricular fibrillation","onset_id":null,"reference":"OMIM:609621","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"1d48e05d706416b0167adbc3c13bff3137821e01969abfcdfe49dcfa54318938","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609622","disease_name":"Short QT syndrome 3","evidence":"PCS","frequency_raw":"1/4","hpo_id":"HP:0001962","is_excluded":false,"label":"Palpitations","onset_id":null,"reference":"PMID:22155372;PMID:15761194;PMID:23440193","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"1e2b9a5b09645d9b0d23453bcfbd6718e088fffa14219fdcab20540b607343d3","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609621","disease_name":"Short QT syndrome 2","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0012232","is_excluded":false,"label":"Shortened QT interval","onset_id":null,"reference":"PMID:15890322","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"2200bab2980c98a09c5bb0d30334070b6eec3e9597c6490f723891ab78fd4ed1","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609622","disease_name":"Short QT syndrome 3","evidence":"PCS","frequency_raw":"1/4","hpo_id":"HP:0031972","is_excluded":false,"label":"Presyncope","onset_id":null,"reference":"PMID:22155372;PMID:15761194;PMID:23440193","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"26cbfbca255b3a0b4d498d289385bb53efa1ac50062bd1cb206b6707c1529aed","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:620231","disease_name":"Short QT syndrome 7","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001279","is_excluded":false,"label":"Syncope","onset_id":null,"reference":"PMID:29167417","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"2eea1e03908d3d4442b949c94d4ad6ddf5d4062719526b516617bf573e377fe3","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609620","disease_name":"Short QT syndrome 1","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001962","is_excluded":false,"label":"Palpitations","onset_id":null,"reference":"PMID:12925462","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"3cfb1ed8216b4807b50940f06d744815ab4a0d0d547dc4344ac7a0195b86c216","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609621","disease_name":"Short QT syndrome 2","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0005110","is_excluded":false,"label":"Atrial fibrillation","onset_id":null,"reference":"PMID:15890322","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"5bfd884274fba8e9d859a8aacf984c09f0521a725d1c271b57792f2da7160b3d","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609621","disease_name":"Short QT syndrome 2","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0001662","is_excluded":false,"label":"Bradycardia","onset_id":null,"reference":"OMIM:609621","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"687ab8e718dbb8f5a019a8a61060d6285edff622ec7adefcc0f42399ab75ef8e","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040281","hpo_id":"HP:0001662","is_excluded":false,"label":"Bradycardia","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"6f619f007ec2e90abe6eca23f9c15e40a32fa3d704746818d6fef05b8db8c413","raw":{"aspect":"P","body_system":"other","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0001645","is_excluded":false,"label":"Sudden cardiac death","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"749edd2760f2e85e4ab30b07fdd6e63bdeb84ba313b0c5af0bb0cc94c015baf8","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:620231","disease_name":"Short QT syndrome 7","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0012232","is_excluded":false,"label":"Shortened QT interval","onset_id":null,"reference":"PMID:29167417","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"7720fde7a428c2df7c0b5a01e4f9dbd6bb60eb3612c06de5713accecf733022c","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609622","disease_name":"Short QT syndrome 3","evidence":"PCS","frequency_raw":"4/4","hpo_id":"HP:0012232","is_excluded":false,"label":"Shortened QT interval","onset_id":null,"reference":"PMID:22155372;PMID:15761194;PMID:23440193","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"793236acb23468492c562db141c67258215deee226762ac22433fe56fe0372a3","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0005110","is_excluded":false,"label":"Atrial fibrillation","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"7a0a74e6c5072e2474c952f07668335002873f6d194413ee4f6c01facd7b317f","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609621","disease_name":"Short QT syndrome 2","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001279","is_excluded":false,"label":"Syncope","onset_id":null,"reference":"PMID:15890322","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"7fec013ad3e3197e162153edb0d31fc2bd8f64b12709ea41b20d90237284df7e","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:620231","disease_name":"Short QT syndrome 7","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001695","is_excluded":false,"label":"Cardiac arrest","onset_id":null,"reference":"PMID:29167417","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"929dcbc60a277291bacebaefb503dd563d87279dc441d96aa79e02cea4b17303","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609620","disease_name":"Short QT syndrome 1","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001279","is_excluded":false,"label":"Syncope","onset_id":null,"reference":"PMID:12925462","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"991aee72fc6b0896dab06b23e41d2257f65f547c97b508ca35167cb91bbfc570","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0001678","is_excluded":false,"label":"Atrioventricular block","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"count","key":"9ce1ef0050d3a729f39889e5a2104fb0ff8ca654c39e0312ffc01bda8a0312ca","raw":{"aspect":"P","body_system":"other","disease_id":"OMIM:609622","disease_name":"Short QT syndrome 3","evidence":"PCS","frequency_raw":"0/4","hpo_id":"HP:0001645","is_excluded":true,"label":"Sudden cardiac death","onset_id":null,"reference":"PMID:22155372;PMID:15761194;PMID:23440193","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"a14ea5eb2615ce1140d040f2f4299f60d0d4160be3fe042beb3ee1873b81f65f","raw":{"aspect":"P","body_system":"other","disease_id":"OMIM:620231","disease_name":"Short QT syndrome 7","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001645","is_excluded":false,"label":"Sudden cardiac death","onset_id":null,"reference":"PMID:29167417","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"ac92dea5edd44dc5d67c9c95af5792edf8a044249911082a23ede0f7d22fe27c","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0001279","is_excluded":false,"label":"Syncope","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"count","key":"b547719f70651450caf86aae11ca5f4af7faac1584226beb9bdc252db0345476","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609622","disease_name":"Short QT syndrome 3","evidence":"PCS","frequency_raw":"2/4","hpo_id":"HP:0004757","is_excluded":false,"label":"Paroxysmal atrial fibrillation","onset_id":null,"reference":"PMID:22155372;PMID:15761194;PMID:23440193","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"b705474e695614912aabda3bcb4f697333132e0c62e29de8f30f718ce84a421a","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0001962","is_excluded":false,"label":"Palpitations","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"b7ae630e536713574a48a0aa71a7d9f0bb0d60ac5d0d58523f89befbc81e5b2e","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0004308","is_excluded":false,"label":"Ventricular arrhythmia","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"c1d7830688cd9e54a7204a6005f0bdcf5aa88c3467fffad70280ed5c468b5f42","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:620231","disease_name":"Short QT syndrome 7","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001663","is_excluded":false,"label":"Ventricular fibrillation","onset_id":null,"reference":"PMID:29167417","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"d4477712b5b26c421d533508e5d8f8cbcdbe1c4d4e1b42f76732561efa765942","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609620","disease_name":"Short QT syndrome 1","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0012232","is_excluded":false,"label":"Shortened QT interval","onset_id":null,"reference":"PMID:14676148","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"e4a4484dcad679810f4aa287ddf4b67dbc1150e609986a1c44b75497d586a536","raw":{"aspect":"P","body_system":"other","disease_id":"OMIM:609621","disease_name":"Short QT syndrome 2","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001645","is_excluded":false,"label":"Sudden cardiac death","onset_id":null,"reference":"PMID:15890322","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"ef135bad1c8751ea912ba1c2e0ee3ef01184174e2e61eca8d3168b69e4c6fa9a","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"ORPHA:51083","disease_name":"Congenital short QT syndrome","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0001663","is_excluded":false,"label":"Ventricular fibrillation","onset_id":null,"reference":"ORPHA:51083","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"f1499ebbbd1d889df230837dcc42bf833f4e74373ccb69e49513392669c87ad1","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609620","disease_name":"Short QT syndrome 1","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0004757","is_excluded":false,"label":"Paroxysmal atrial fibrillation","onset_id":null,"reference":"PMID:14676148","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"f3aa6f1a6dcc99845324fdb9270ba2364f80c007f3994819859d607513048abc","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:609622","disease_name":"Short QT syndrome 3","evidence":"PCS","frequency_raw":"1/4","hpo_id":"HP:0012663","is_excluded":false,"label":"Mildly reduced left ventricular ejection fraction","onset_id":null,"reference":"PMID:22155372;PMID:15761194;PMID:23440193","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"ff71ccc0688736ca27632ddfabc79622f24176c9b335c0979236e43160b55172","raw":{"aspect":"P","body_system":"other","disease_id":"OMIM:609620","disease_name":"Short QT syndrome 1","evidence":"PCS","frequency_raw":null,"hpo_id":"HP:0001645","is_excluded":false,"label":"Sudden cardiac death","onset_id":null,"reference":"PMID:14676148","source_release":"2026-06-23"},"sourceGroups":["published"]}],"referenceLabels":{},"references":{"causeHtml":"<ul><li><a href=\"https://medlineplus.gov/genetics/condition/short-qt-syndrome\">Short QT syndrome</a></li></ul>","identityNote":"MONDO cross-references identify native condition entries. Ancestor membership does not transfer phenotype values between groups.","importantHtml":""},"sections":[{"bodyHtml":"<p>Mutations in the KCNH2, KCNJ2, and KCNQ1 genes can cause short QT syndrome. These genes provide instructions for making channels that transport positively charged atoms (ions) of potassium out of cells. In cardiac muscle, these ion channels play critical roles in maintaining the heart&#x27;s normal rhythm. Mutations in the KCNH2, KCNJ2, or KCNQ1 gene increase the activity of the channels, which enhances the flow of potassium ions across the membrane of cardiac muscle cells. This change in ion transport alters the electrical activity of the heart and can lead to the abnormal heart rhythms characteristic of short QT syndrome.</p><p>Some affected individuals do not have an identified mutation in the KCNH2, KCNJ2, or KCNQ1 gene. Changes in other genes that have not been identified may cause the disorder in these cases.</p><p class=\"section-source\"><a href=\"https://medlineplus.gov/genetics/condition/short-qt-syndrome/#causes\">MedlinePlus Genetics: Causes</a></p>","key":"forms","title":"What causes Short QT syndrome?"},{"bodyHtml":"<p>If untreated, the arrhythmia associated with short QT syndrome can lead to a variety of signs and symptoms, from dizziness and fainting (syncope) to cardiac arrest and sudden death. These signs and symptoms can occur any time from early infancy to old age. This condition may explain some cases of sudden infant death syndrome (SIDS), which is a major cause of unexplained death in babies younger than 1 year. However, some people with short QT syndrome never experience any health problems associated with the condition.</p><p class=\"section-source\">Source: <a href=\"https://medlineplus.gov/genetics/condition/short-qt-syndrome\">MedlinePlus Genetics</a></p>","key":"overview","title":"Condition overview"}],"sharedSources":[],"slug":"short-qt-syndrome","sourceDocuments":[{"name":"Short QT syndrome","reviewed":"2013-06","sections":{"causes":{"fetchedAt":"2026-10-20T20:24:58.230423+00:00","label":"Causes","pageSha256":"ff224947ae1325199fc1ca60506f2aea88dbca81f2499ed8b70a6e14feca8c92","sourceUrl":"https://medlineplus.gov/genetics/condition/short-qt-syndrome/#causes","status":"available"}},"source_release":"2026-10-01","url":"https://medlineplus.gov/genetics/condition/short-qt-syndrome"}],"sourceNote":"MedlinePlus descriptions and Causes; original HPO annotations.","takeawayHtml":"Cause explanations are from MedlinePlus Genetics. Feature values below retain their original sources and patient groups.","title":"Short QT syndrome"},"schemaVersion":1}