{"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:0009706/OMIM:255125","label":"Myopathy with exercise intolerance, Swedish type","mondoId":"MONDO:0009706","onsetQualifier":null,"recordKeys":["0377c2802c953142e409e426942eea41d1a87756dd11d78918ded07e12d4a229","0b0397259d530252365adf73d2a3887fa42f5bcafb909638c3d979c1f4dae543","1376afff2195eec4c615faea4bd336ddfdf90b92b7278489c70f23bfca5c5cfa","15e4b4deda65b25f3256d8b36a9a99c8b639bc25367f687c9b11b32b4c6fe6d6","2463117edeb458692cacf4560fb5612daa834cb5a760b12f83894214df35f70b","2af892eb6e554c1eb29d11ac33910a134ad021b714cd877096a8712c311dda9c","2f6a05d01d0ffb9e12aa3c7c740f37e03203dbe4e3669fa89ba3d4e2103df631","45753516493cd1d53d67f2e6fa8e710dac8179ad9e418db06bea7279c69481ef","5f022586bf14dc4ae5316cd0340716db19abe3afffabca92627fbd6772a0a8d2","6627d30c90c94cf43f54d74dd8f14934a34e0c6a38453148eec1b2bd56ab78b9","6bcc1a7a1f4d41ce420a64ca1fdc27c548be84faeda0a10a495424470a048a65","7530297a768e720904d1c678656674c99edfe70403e2ebdeb8303b4ee54d5fec","7b77d74a0fd218d6500c38bc6c3d9327c6f299167f086457ddb19fef6c469506","809bda1e5ff1866afad13e7cf66ce7af9acb49dab68541f51c8370329dde896d","80a00e7512b600c7983778035c6a70d133e99d35a541ba8daccaa46b761888cc","82245dfa3ee0712e50397de9678d7785694e2a21d2e76c81e04dc871047929f0","8f81b55db38f8333b5be915b374be060a4583d22b0660c0f9c957c55c97d80e7","91924712c05d492db719722322d5f640778cddd642e201ce97ea54f3acc0aebe","952a2019d3b61724c6cf4678a81c21e35ba6f5c7f918497cab1b7df9da6f415b","96a9d554268872ec18ccefa44977ca2922243b8b92ddca3387efe120b0dcc383","a23c5412d4af839b324030178875cd1094a8ebfd1869817d0855305deba7f12f","abafb7408b2b02b55efced7f44e7a179e78103e8cabe8a4f01211a36b596c472","b3dc21f2bf2e7fd28a469b226df8f8373e73901820ff161efffb041465e2eea8","c1bb4b43bd247e71f62d6d2e38a600e92a39d3163093126be2b0d22ad4437690","c62a348a24ce4b04e3cd58f71762661174ffd658f75c0a3b2160531e43366618","cc1ba43047035ecba7ce5acc410e2dabf1a8eff9ed3df36e3eb32b4ad8ac2cc3","d5abc950b330ee383bca10ec2e3e95666e890acdd30ed0e3e2099ccb77abdb07","dc8e53e2b4201e7d66791b4715ff4c86ae8c469d33731bcb07782484b39b6821","e8f91cfbfba80ac66faed813ba512a1c7cb3a6333c7c9f82e26a9023c4068b59","ed62001d66208aede427f0349813f6d2fa3f4f58064f67b5b21f90f78f0f2074","f08bc7814f671c8818ea393b17dccd57e0c624bd6185f2e8a9b037a211c5c351","fc3be9930313009709a38cd823cf4bef95d1fdf20d4d192c4481ac19e88f3b25"],"recordQualifiers":{},"scopeLabel":"OMIM:255125","sourceIds":["OMIM:255125"],"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:0009706/OMIM:255125"],"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":18,"emptyColumnKeys":[],"hpoRelease":"2026-06-23","narrativeSourceChanges":[],"records":32,"sourceGroups":{"omim":14,"orphanet":0,"published":18}},"features":[{"hpoId":"HP:0008306","label":"Abnormal iron deposition in mitochondria","primary":false},{"hpoId":"HP:0001903","label":"Anemia","primary":false},{"hpoId":"HP:0001284","label":"Areflexia","primary":false},{"hpoId":"HP:0001488","label":"Bilateral ptosis","primary":false},{"hpoId":"HP:0011923","label":"Decreased activity of mitochondrial complex I","primary":false},{"hpoId":"HP:0008314","label":"Decreased activity of mitochondrial complex II","primary":false},{"hpoId":"HP:0011924","label":"Decreased activity of mitochondrial complex III","primary":false},{"hpoId":"HP:0008347","label":"Decreased activity of mitochondrial complex IV","primary":false},{"hpoId":"HP:0001882","label":"Decreased total leukocyte count","primary":false},{"hpoId":"HP:0002460","label":"Distal muscle weakness","primary":false},{"hpoId":"HP:0002094","label":"Dyspnea","primary":false},{"hpoId":"HP:0003388","label":"Easy fatigability","primary":false},{"hpoId":"HP:0003236","label":"Elevated circulating creatine kinase activity","primary":false},{"hpoId":"HP:0003546","label":"Exercise intolerance","primary":false},{"hpoId":"HP:0002359","label":"Frequent falls","primary":false},{"hpoId":"HP:0001288","label":"Gait disturbance","primary":false},{"hpoId":"HP:0001252","label":"Hypotonia","primary":false},{"hpoId":"HP:0002151","label":"Increased circulating lactate concentration","primary":false},{"hpoId":"HP:0012240","label":"Increased intramyocellular lipid droplets","primary":false},{"hpoId":"HP:0003557","label":"Increased variability in muscle fiber diameter","primary":false},{"hpoId":"HP:0003128","label":"Lactic acidosis","primary":false},{"hpoId":"HP:0003737","label":"Mitochondrial myopathy","primary":false},{"hpoId":"HP:0003394","label":"Muscle spasm","primary":false},{"hpoId":"HP:0001324","label":"Muscle weakness","primary":false},{"hpoId":"HP:0002913","label":"Myoglobinuria","primary":false},{"hpoId":"HP:0003198","label":"Myopathy","primary":false},{"hpoId":"HP:0000597","label":"Ophthalmoparesis","primary":false},{"hpoId":"HP:0001962","label":"Palpitations","primary":false},{"hpoId":"HP:0003201","label":"Rhabdomyolysis","primary":false},{"hpoId":"HP:0001924","label":"Sideroblastic anemia","primary":false},{"hpoId":"HP:0003202","label":"Skeletal muscle atrophy","primary":false},{"hpoId":"HP:0003548","label":"Subsarcolemmal accumulations of abnormally shaped mitochondria","primary":false}],"ledeHtml":"Myopathy with deficiency of iron-sulfur cluster assembly enzyme is an inherited disorder that primarily affects muscles used for movement (skeletal muscles). This condition does not usually affect other types of muscle, such as the heart (cardiac) muscle.","mondoId":"MONDO:0009706","records":[{"frequencyKind":"count","key":"0377c2802c953142e409e426942eea41d1a87756dd11d78918ded07e12d4a229","raw":{"aspect":"P","body_system":"blood","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0001882","is_excluded":false,"label":"Decreased total leukocyte count","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"0b0397259d530252365adf73d2a3887fa42f5bcafb909638c3d979c1f4dae543","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0002460","is_excluded":false,"label":"Distal muscle weakness","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"1376afff2195eec4c615faea4bd336ddfdf90b92b7278489c70f23bfca5c5cfa","raw":{"aspect":"P","body_system":"eye","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0000597","is_excluded":false,"label":"Ophthalmoparesis","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"15e4b4deda65b25f3256d8b36a9a99c8b639bc25367f687c9b11b32b4c6fe6d6","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002913","is_excluded":false,"label":"Myoglobinuria","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"2463117edeb458692cacf4560fb5612daa834cb5a760b12f83894214df35f70b","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0001288","is_excluded":false,"label":"Gait disturbance","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"2af892eb6e554c1eb29d11ac33910a134ad021b714cd877096a8712c311dda9c","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0008314","is_excluded":false,"label":"Decreased activity of mitochondrial complex II","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"2f6a05d01d0ffb9e12aa3c7c740f37e03203dbe4e3669fa89ba3d4e2103df631","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0003737","is_excluded":false,"label":"Mitochondrial myopathy","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"45753516493cd1d53d67f2e6fa8e710dac8179ad9e418db06bea7279c69481ef","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0001284","is_excluded":false,"label":"Areflexia","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"5f022586bf14dc4ae5316cd0340716db19abe3afffabca92627fbd6772a0a8d2","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0012240","is_excluded":false,"label":"Increased intramyocellular lipid droplets","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"6627d30c90c94cf43f54d74dd8f14934a34e0c6a38453148eec1b2bd56ab78b9","raw":{"aspect":"P","body_system":"blood","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001924","is_excluded":false,"label":"Sideroblastic anemia","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"6bcc1a7a1f4d41ce420a64ca1fdc27c548be84faeda0a10a495424470a048a65","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0003198","is_excluded":false,"label":"Myopathy","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"7530297a768e720904d1c678656674c99edfe70403e2ebdeb8303b4ee54d5fec","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0008306","is_excluded":false,"label":"Abnormal iron deposition in mitochondria","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"7b77d74a0fd218d6500c38bc6c3d9327c6f299167f086457ddb19fef6c469506","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0002359","is_excluded":false,"label":"Frequent falls","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"809bda1e5ff1866afad13e7cf66ce7af9acb49dab68541f51c8370329dde896d","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0003236","is_excluded":false,"label":"Elevated circulating creatine kinase activity","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"80a00e7512b600c7983778035c6a70d133e99d35a541ba8daccaa46b761888cc","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0003201","is_excluded":false,"label":"Rhabdomyolysis","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"82245dfa3ee0712e50397de9678d7785694e2a21d2e76c81e04dc871047929f0","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001324","is_excluded":false,"label":"Muscle weakness","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"8f81b55db38f8333b5be915b374be060a4583d22b0660c0f9c957c55c97d80e7","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0011924","is_excluded":false,"label":"Decreased activity of mitochondrial complex III","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"91924712c05d492db719722322d5f640778cddd642e201ce97ea54f3acc0aebe","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0003394","is_excluded":false,"label":"Muscle spasm","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"952a2019d3b61724c6cf4678a81c21e35ba6f5c7f918497cab1b7df9da6f415b","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0003548","is_excluded":false,"label":"Subsarcolemmal accumulations of abnormally shaped mitochondria","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"96a9d554268872ec18ccefa44977ca2922243b8b92ddca3387efe120b0dcc383","raw":{"aspect":"P","body_system":"respiratory","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002094","is_excluded":false,"label":"Dyspnea","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"a23c5412d4af839b324030178875cd1094a8ebfd1869817d0855305deba7f12f","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002151","is_excluded":false,"label":"Increased circulating lactate concentration","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"abafb7408b2b02b55efced7f44e7a179e78103e8cabe8a4f01211a36b596c472","raw":{"aspect":"P","body_system":"eye","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0001488","is_excluded":false,"label":"Bilateral ptosis","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"b3dc21f2bf2e7fd28a469b226df8f8373e73901820ff161efffb041465e2eea8","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0003202","is_excluded":false,"label":"Skeletal muscle atrophy","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"c1bb4b43bd247e71f62d6d2e38a600e92a39d3163093126be2b0d22ad4437690","raw":{"aspect":"P","body_system":"cardiovascular","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001962","is_excluded":false,"label":"Palpitations","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"c62a348a24ce4b04e3cd58f71762661174ffd658f75c0a3b2160531e43366618","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0011923","is_excluded":false,"label":"Decreased activity of mitochondrial complex I","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"cc1ba43047035ecba7ce5acc410e2dabf1a8eff9ed3df36e3eb32b4ad8ac2cc3","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0003128","is_excluded":false,"label":"Lactic acidosis","onset_id":null,"reference":"OMIM:255125","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"d5abc950b330ee383bca10ec2e3e95666e890acdd30ed0e3e2099ccb77abdb07","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0008347","is_excluded":false,"label":"Decreased activity of mitochondrial complex IV","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"dc8e53e2b4201e7d66791b4715ff4c86ae8c469d33731bcb07782484b39b6821","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0003557","is_excluded":false,"label":"Increased variability in muscle fiber diameter","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"e8f91cfbfba80ac66faed813ba512a1c7cb3a6333c7c9f82e26a9023c4068b59","raw":{"aspect":"P","body_system":"other","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0003546","is_excluded":false,"label":"Exercise intolerance","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"ed62001d66208aede427f0349813f6d2fa3f4f58064f67b5b21f90f78f0f2074","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0001252","is_excluded":false,"label":"Hypotonia","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"f08bc7814f671c8818ea393b17dccd57e0c624bd6185f2e8a9b037a211c5c351","raw":{"aspect":"P","body_system":"blood","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0001903","is_excluded":false,"label":"Anemia","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"fc3be9930313009709a38cd823cf4bef95d1fdf20d4d192c4481ac19e88f3b25","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:255125","disease_name":"Myopathy with exercise intolerance, Swedish type","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0003388","is_excluded":false,"label":"Easy fatigability","onset_id":null,"reference":"PMID:29079705","source_release":"2026-06-23"},"sourceGroups":["published"]}],"referenceLabels":{},"references":{"causeHtml":"<ul><li><a href=\"https://medlineplus.gov/genetics/condition/myopathy-with-deficiency-of-iron-sulfur-cluster-assembly-enzyme\">Myopathy with deficiency of iron-sulfur cluster assembly enzyme</a></li></ul>","identityNote":"MONDO cross-references identify native condition entries. Ancestor membership does not transfer phenotype values between groups.","importantHtml":""},"sections":[{"bodyHtml":"<p>Myopathy with deficiency of iron-sulfur cluster assembly enzyme is caused by mutations in the ISCU gene. This gene provides instructions for making a protein called the iron-sulfur cluster assembly enzyme. As its name suggests, this enzyme is involved in the formation of clusters of iron and sulfur atoms (Fe-S clusters). These clusters are critical for the function of many different proteins, including those needed for DNA repair and the regulation of iron levels. Proteins containing Fe-S clusters are also necessary for energy production within mitochondria, which are the cell structures that convert the energy from food into a form that cells can use.</p><p>Mutations in the ISCU gene severely limit the amount of iron-sulfur cluster assembly enzyme that is made in cells. A shortage of this enzyme prevents the normal production of proteins that contain Fe-S clusters, which disrupts a variety of cellular activities. A reduction in the amount of iron-sulfur cluster assembly enzyme is particularly damaging to skeletal muscle cells. Within the mitochondria of these cells, a lack of this enzyme causes problems with energy production and an overload of iron. These defects lead to exercise intolerance and the other features of myopathy with deficiency of iron-sulfur cluster assembly enzyme.</p><p class=\"section-source\"><a href=\"https://medlineplus.gov/genetics/condition/myopathy-with-deficiency-of-iron-sulfur-cluster-assembly-enzyme/#causes\">MedlinePlus Genetics: Causes</a></p>","key":"forms","title":"What causes Myopathy with deficiency of iron-sulfur cluster assembly enzyme?"},{"bodyHtml":"<p>From early childhood, affected individuals experience extreme fatigue in response to physical activity (exercise intolerance). Mild exertion results in a rapid heartbeat (tachycardia), shortness of breath, and muscle weakness and pain. However, people with this condition typically have normal muscle strength when they are at rest.</p><p>Prolonged or recurrent physical activity causes more severe signs and symptoms, including a breakdown of muscle tissue (rhabdomyolysis). The destruction of muscle tissue releases a protein called myoglobin, which is processed by the kidneys and released in the urine (myoglobinuria). Myoglobin causes the urine to be red or brown. This protein can also damage the kidneys, in some cases leading to life-threatening kidney failure.</p><p>In most affected individuals, the muscle problems associated with this condition do not worsen with time. However, at least two people with a severe variant of this disorder have experienced progressive muscle weakness and wasting starting in childhood.</p><p class=\"section-source\">Source: <a href=\"https://medlineplus.gov/genetics/condition/myopathy-with-deficiency-of-iron-sulfur-cluster-assembly-enzyme\">MedlinePlus Genetics</a></p>","key":"overview","title":"Condition overview"}],"sharedSources":[],"slug":"myopathy-with-deficiency-of-iron-sulfur-cluster-assembly-enzyme","sourceDocuments":[{"name":"Myopathy with deficiency of iron-sulfur cluster assembly enzyme","reviewed":"2009-11","sections":{"causes":{"fetchedAt":"2026-10-20T20:23:38.908112+00:00","label":"Causes","pageSha256":"00ccff24dff4a51b6c8e3fec988ce98eedf254cb589d37264b233be8416e62c6","sourceUrl":"https://medlineplus.gov/genetics/condition/myopathy-with-deficiency-of-iron-sulfur-cluster-assembly-enzyme/#causes","status":"available"}},"source_release":"2026-10-01","url":"https://medlineplus.gov/genetics/condition/myopathy-with-deficiency-of-iron-sulfur-cluster-assembly-enzyme"}],"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":"Myopathy with deficiency of iron-sulfur cluster assembly enzyme"},"schemaVersion":1}