{"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:0010397/OMIM:300673","label":"Encephalopathy, neonatal severe, due to mecp2 mutations","mondoId":"MONDO:0010397","onsetQualifier":null,"recordKeys":["0028e2cd927e870c24a1de652af07a662b435417c6717fbf9f3d518ef40c4599","19e75b84aa390f6a714ed21881b8503e926237e3e5343934b5944cb5700989be","1f3ad1ca846c41d4e0b5bcfb3927ac33d6cd58fec4d1c4793a4efab462c47be8","3ca1491b8d98fa609b76785a4fac7b97216d0ff9aa08cdd930dff65e710fecb9","4ca114f9a68a3d5840ec3e51a06783f12a2df8b0cfba8747249827eaddbe5823","59cf1615db25f5f38a3ca8d7304179856905c0ede86cfdfdb82f060c814e8f2b","66e46f139893a1ced498087045a1507b655dee98e38fe6d3b8e5e81a8de04657","779e0885a84edb9ed9d15219b59d5a3b2c816c43b7d16f241091f9aafe0f9f3d","99fe2c16c3202d566dc783c5ae4a693f46a167d859e541b2de45032a14e0bce8","9d3bad4727b81f28709b9d54467887e45fa95802baba6b0081fea241195686ca","a204c693f0908d9b5f4c3b64b8eecc947745098b83abcde3a6d899e403cb9c80","ab35a2d64083b6bca2871065420545f224478d9decc2cfcc69307e46d3933859","b87e16e0cf2a42263834a585d0f261c8a1952d16fc370a733b294671dfec49eb","c2b8080b7b83ca379b6340bb7a8333a1a0412a494f8992ea4427d007c0ed8145","d0907c1d0f856922f700c94d5d3c2518e7679a5b071d4d8203df31ce21ee3278","d4bb68ef01b7a42bc2c0174975f1ba63fa0410721266818976e3806d4edf70f2","e9d7956e8a98beac708f57911ed7c857817afa560739901366aa41d817896e5a","fe527786a2aed5e11a0545a6a92e316811e7c3a9ad2b42eab52dae7842391d8d"],"recordQualifiers":{},"scopeLabel":"OMIM:300673","sourceIds":["OMIM:300673"],"sourceScope":"This column retains the native source entry. It is not a pooled estimate for the umbrella condition."},{"gene":"","key":"MONDO:0010397/ORPHA:209370","label":"MECP2-related severe neonatal encephalopathy","mondoId":"MONDO:0010397","onsetQualifier":null,"recordKeys":["02652cd4c1a978ad4e36878be0b2590c3a20e769447ee0f4ccea71bbd60c2024","09ab770b33a69a69cc00e86e43d57b077834b2a67d1bd11a620050abceb09891","104a4fb539ff42e9c8efb9b9aadada4295767af21ba9e2f31268a7adf0f6f055","131648a55e7fff6af7498e5d8e711b42c279359f1f264a9aebe554a0480f136d","1d29f475dc50dd9c5f417ccbe89dfd0e3b9daf389817d61f29838913b317b5c1","21b54ab9a192eca78b70c9c27c24634505c83f80314d5e414c16934d0648743b","37405beb04274c77d157b58ded5b14b0ee17151e5eca8a23b4c91c0e514e097f","47ee1560d78beeec5e3b7cc8b3858b58530bcd6416bea7b21b49887dd348b66c","4969f1f3e5ac28138a44547e08c0a59d3e4e11cd2ad9315244562de5a39e1f8f","75805a797b722711a08b8b8f620f511500e10c5b6cef1b07438fc34f662ee3f4","88c8cec753d7bc2b6707cf4b463033312af7b89291372019c9256fe608514ec6","89900b6608186e97910b41da7f13729448af45ad6614c63b380a7a5ebe461edb","8ade8f3dbb9003d54145dde6b3562726158b1ee39859313c3d68e0ea723c96f8","a2aa4f18bee4a26a7158abed239fa06aebfd41994e307c1cbf958d0be84bf260","ab8f9f98598fdf7a0d3b16d49ea916065378df4bd656aa508a2adedc3290b54d","b6cbea028fd0fc82f20d512677749dc143f713ed7aea15b58a1aebdbfe32e108","c676a70d5ab350042b5e4c9ac9fb5a6fba3a3ace4c776f325efec9b817e8483f","ce95feb6730b6a4ad595aeeb88f653b4e53c0e675f3c9d938259f63c9d1aa5c6","d8affb3c87c9b3ed2bf5f5c3f2259242c683e5867563d20858c8aba937e21af8"],"recordQualifiers":{},"scopeLabel":"ORPHA:209370","sourceIds":["ORPHA:209370"],"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:0010397/OMIM:300673","MONDO:0010397/ORPHA:209370"],"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":1,"emptyColumnKeys":[],"hpoRelease":"2026-06-23","narrativeSourceChanges":[],"records":37,"sourceGroups":{"omim":17,"orphanet":19,"published":1}},"features":[{"hpoId":"HP:0002104","label":"Apnea","primary":false},{"hpoId":"HP:0008936","label":"Axial hypotonia","primary":false},{"hpoId":"HP:0002069","label":"Bilateral tonic-clonic seizure","primary":false},{"hpoId":"HP:0007110","label":"Central hypoventilation","primary":false},{"hpoId":"HP:0002059","label":"Cerebral atrophy","primary":false},{"hpoId":"HP:0002353","label":"EEG abnormality","primary":false},{"hpoId":"HP:0010843","label":"EEG with focal slow activity","primary":false},{"hpoId":"HP:0001298","label":"Encephalopathy","primary":false},{"hpoId":"HP:0001508","label":"Failure to thrive","primary":false},{"hpoId":"HP:0008872","label":"Feeding difficulties in infancy","primary":false},{"hpoId":"HP:0002020","label":"Gastroesophageal reflux","primary":false},{"hpoId":"HP:0011471","label":"Gastrostomy tube feeding in infancy","primary":false},{"hpoId":"HP:0008935","label":"Generalized neonatal hypotonia","primary":false},{"hpoId":"HP:0001263","label":"Global developmental delay","primary":false},{"hpoId":"HP:0001510","label":"Growth delay","primary":false},{"hpoId":"HP:0000218","label":"High palate","primary":false},{"hpoId":"HP:0001347","label":"Hyperreflexia","primary":false},{"hpoId":"HP:0001249","label":"Intellectual disability","primary":false},{"hpoId":"HP:0004305","label":"Involuntary movements","primary":false},{"hpoId":"HP:0000252","label":"Microcephaly","primary":false},{"hpoId":"HP:0010841","label":"Multifocal epileptiform discharges","primary":false},{"hpoId":"HP:0001336","label":"Myoclonus","primary":false},{"hpoId":"HP:0002126","label":"Polymicrogyria","primary":false},{"hpoId":"HP:0002033","label":"Poor suck","primary":false},{"hpoId":"HP:0000253","label":"Progressive microcephaly","primary":false},{"hpoId":"HP:0002093","label":"Respiratory insufficiency","primary":false},{"hpoId":"HP:0002063","label":"Muscle rigidity","primary":false},{"hpoId":"HP:0001250","label":"Seizures","primary":false},{"hpoId":"HP:0011344","label":"Severe global developmental delay","primary":false},{"hpoId":"HP:0010864","label":"Severe intellectual disability","primary":false},{"hpoId":"HP:0001257","label":"Spasticity","primary":false}],"ledeHtml":"MECP2-related severe neonatal encephalopathy is a neurological disorder that primarily affects males and causes brain dysfunction (encephalopathy). Affected males have a small head size (microcephaly), poor muscle tone (hypotonia) in infancy, movement disorders, rigidity, and seizures. Infants with this condition appear normal at birth but then develop severe encephalopathy within the first week of life. These babies experience poor feeding, leading to a failure to gain weight and grow at the expected rate (failure to thrive). Individuals with MECP2-related severe neonatal encephalopathy have severe to profound intellectual disability. Affected males have breathing problems, with some having episodes in which breathing slows or stops for short periods (apnea). As the child ages, the apnea episodes tend to last longer, especially during sleep, and affected babies often require use of a machine to help regulate their breathing (mechanical ventilation). Most males with MECP2-related severe neonatal encephalopathy do not live past the age of 2 because of respiratory failure.","mondoId":"MONDO:0010397","records":[{"frequencyKind":"count","key":"0028e2cd927e870c24a1de652af07a662b435417c6717fbf9f3d518ef40c4599","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"PCS","frequency_raw":"1/1","hpo_id":"HP:0001298","is_excluded":false,"label":"Encephalopathy","onset_id":"HP:0003577","reference":"PMID:10577905","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"range","key":"02652cd4c1a978ad4e36878be0b2590c3a20e769447ee0f4ccea71bbd60c2024","raw":{"aspect":"P","body_system":"respiratory","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040281","hpo_id":"HP:0002104","is_excluded":false,"label":"Apnea","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"09ab770b33a69a69cc00e86e43d57b077834b2a67d1bd11a620050abceb09891","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0001250","is_excluded":false,"label":"Seizure","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"104a4fb539ff42e9c8efb9b9aadada4295767af21ba9e2f31268a7adf0f6f055","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0002059","is_excluded":false,"label":"Cerebral atrophy","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"131648a55e7fff6af7498e5d8e711b42c279359f1f264a9aebe554a0480f136d","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040281","hpo_id":"HP:0011344","is_excluded":false,"label":"Severe global developmental delay","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"19e75b84aa390f6a714ed21881b8503e926237e3e5343934b5944cb5700989be","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001249","is_excluded":false,"label":"Intellectual disability","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"1d29f475dc50dd9c5f417ccbe89dfd0e3b9daf389817d61f29838913b317b5c1","raw":{"aspect":"P","body_system":"digestive","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0011471","is_excluded":false,"label":"Gastrostomy tube feeding in infancy","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"1f3ad1ca846c41d4e0b5bcfb3927ac33d6cd58fec4d1c4793a4efab462c47be8","raw":{"aspect":"P","body_system":"growth","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001508","is_excluded":false,"label":"Failure to thrive","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"21b54ab9a192eca78b70c9c27c24634505c83f80314d5e414c16934d0648743b","raw":{"aspect":"P","body_system":"growth","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0001510","is_excluded":false,"label":"Growth delay","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"37405beb04274c77d157b58ded5b14b0ee17151e5eca8a23b4c91c0e514e097f","raw":{"aspect":"P","body_system":"respiratory","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040281","hpo_id":"HP:0002093","is_excluded":false,"label":"Respiratory insufficiency","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"3ca1491b8d98fa609b76785a4fac7b97216d0ff9aa08cdd930dff65e710fecb9","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001336","is_excluded":false,"label":"Myoclonus","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"47ee1560d78beeec5e3b7cc8b3858b58530bcd6416bea7b21b49887dd348b66c","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0004305","is_excluded":false,"label":"Involuntary movements","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"4969f1f3e5ac28138a44547e08c0a59d3e4e11cd2ad9315244562de5a39e1f8f","raw":{"aspect":"P","body_system":"digestive","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0002020","is_excluded":false,"label":"Gastroesophageal reflux","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"4ca114f9a68a3d5840ec3e51a06783f12a2df8b0cfba8747249827eaddbe5823","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001250","is_excluded":false,"label":"Seizure","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"59cf1615db25f5f38a3ca8d7304179856905c0ede86cfdfdb82f060c814e8f2b","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0010864","is_excluded":false,"label":"Severe intellectual disability","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"66e46f139893a1ced498087045a1507b655dee98e38fe6d3b8e5e81a8de04657","raw":{"aspect":"P","body_system":"digestive","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0008872","is_excluded":false,"label":"Feeding difficulties in infancy","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"75805a797b722711a08b8b8f620f511500e10c5b6cef1b07438fc34f662ee3f4","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0010843","is_excluded":false,"label":"EEG with focal slow activity","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"779e0885a84edb9ed9d15219b59d5a3b2c816c43b7d16f241091f9aafe0f9f3d","raw":{"aspect":"P","body_system":"respiratory","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002093","is_excluded":false,"label":"Respiratory insufficiency","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"88c8cec753d7bc2b6707cf4b463033312af7b89291372019c9256fe608514ec6","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0008935","is_excluded":false,"label":"Generalized neonatal hypotonia","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"89900b6608186e97910b41da7f13729448af45ad6614c63b380a7a5ebe461edb","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0002069","is_excluded":false,"label":"Bilateral tonic-clonic seizure","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"8ade8f3dbb9003d54145dde6b3562726158b1ee39859313c3d68e0ea723c96f8","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0000252","is_excluded":false,"label":"Microcephaly","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"99fe2c16c3202d566dc783c5ae4a693f46a167d859e541b2de45032a14e0bce8","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002063","is_excluded":false,"label":"Rigidity","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"9d3bad4727b81f28709b9d54467887e45fa95802baba6b0081fea241195686ca","raw":{"aspect":"P","body_system":"respiratory","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002104","is_excluded":false,"label":"Apnea","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"a204c693f0908d9b5f4c3b64b8eecc947745098b83abcde3a6d899e403cb9c80","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002126","is_excluded":false,"label":"Polymicrogyria","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"a2aa4f18bee4a26a7158abed239fa06aebfd41994e307c1cbf958d0be84bf260","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040281","hpo_id":"HP:0001298","is_excluded":false,"label":"Encephalopathy","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"ab35a2d64083b6bca2871065420545f224478d9decc2cfcc69307e46d3933859","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001263","is_excluded":false,"label":"Global developmental delay","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"ab8f9f98598fdf7a0d3b16d49ea916065378df4bd656aa508a2adedc3290b54d","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0001257","is_excluded":false,"label":"Spasticity","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"b6cbea028fd0fc82f20d512677749dc143f713ed7aea15b58a1aebdbfe32e108","raw":{"aspect":"P","body_system":"digestive","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040282","hpo_id":"HP:0002033","is_excluded":false,"label":"Poor suck","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"b87e16e0cf2a42263834a585d0f261c8a1952d16fc370a733b294671dfec49eb","raw":{"aspect":"P","body_system":"musculoskeletal","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0008936","is_excluded":false,"label":"Axial hypotonia","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"c2b8080b7b83ca379b6340bb7a8333a1a0412a494f8992ea4427d007c0ed8145","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0001347","is_excluded":false,"label":"Hyperreflexia","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"c676a70d5ab350042b5e4c9ac9fb5a6fba3a3ace4c776f325efec9b817e8483f","raw":{"aspect":"P","body_system":"head_and_neck","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0000218","is_excluded":false,"label":"High palate","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"range","key":"ce95feb6730b6a4ad595aeeb88f653b4e53c0e675f3c9d938259f63c9d1aa5c6","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0010841","is_excluded":false,"label":"Multifocal epileptiform discharges","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"d0907c1d0f856922f700c94d5d3c2518e7679a5b071d4d8203df31ce21ee3278","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002353","is_excluded":false,"label":"EEG abnormality","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"d4bb68ef01b7a42bc2c0174975f1ba63fa0410721266818976e3806d4edf70f2","raw":{"aspect":"P","body_system":"digestive","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0002020","is_excluded":false,"label":"Gastroesophageal reflux","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"range","key":"d8affb3c87c9b3ed2bf5f5c3f2259242c683e5867563d20858c8aba937e21af8","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"ORPHA:209370","disease_name":"MECP2-related severe neonatal encephalopathy","evidence":"TAS","frequency_raw":"HP:0040283","hpo_id":"HP:0002126","is_excluded":false,"label":"Polymicrogyria","onset_id":null,"reference":"ORPHA:209370","source_release":"2026-06-23"},"sourceGroups":["orphanet"]},{"frequencyKind":"reported","key":"e9d7956e8a98beac708f57911ed7c857817afa560739901366aa41d817896e5a","raw":{"aspect":"P","body_system":"respiratory","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0007110","is_excluded":false,"label":"Central hypoventilation","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"fe527786a2aed5e11a0545a6a92e316811e7c3a9ad2b42eab52dae7842391d8d","raw":{"aspect":"P","body_system":"nervous_system","disease_id":"OMIM:300673","disease_name":"Encephalopathy, neonatal severe, due to mecp2 mutations","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0000253","is_excluded":false,"label":"Progressive microcephaly","onset_id":null,"reference":"OMIM:300673","source_release":"2026-06-23"},"sourceGroups":["omim"]}],"referenceLabels":{},"references":{"causeHtml":"<ul><li><a href=\"https://medlineplus.gov/genetics/condition/mecp2-related-severe-neonatal-encephalopathy\">MECP2-related severe neonatal encephalopathy</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 MECP2 gene cause MECP2-related severe neonatal encephalopathy. The MECP2 gene provides instructions for making a protein called MeCP2 that is critical for normal brain function. Researchers believe that this protein has several functions, including regulating other genes in the brain by switching them on or off as they are needed. The MeCP2 protein likely plays a role in maintaining the normal function of nerve cells, which ensures that connections (synapses) between these cells form properly. The MeCP2 protein may also control the production of different versions of certain proteins in nerve cells. Although mutations in the MECP2 gene disrupt the normal function of nerve cells, it is unclear how these mutations lead to the signs and symptoms of MECP2-related severe neonatal encephalopathy.</p><p class=\"section-source\"><a href=\"https://medlineplus.gov/genetics/condition/mecp2-related-severe-neonatal-encephalopathy/#causes\">MedlinePlus Genetics: Causes</a></p>","key":"forms","title":"What causes MECP2-related severe neonatal encephalopathy?"},{"bodyHtml":"<p>MECP2-related severe neonatal encephalopathy is the most severe condition in a spectrum of disorders with the same genetic cause. The mildest is PPM-X syndrome, followed by MECP2 duplication syndrome, then Rett syndrome (which exclusively affects females), and finally MECP2-related severe neonatal encephalopathy.</p><p class=\"section-source\">Source: <a href=\"https://medlineplus.gov/genetics/condition/mecp2-related-severe-neonatal-encephalopathy\">MedlinePlus Genetics</a></p>","key":"overview","title":"Condition overview"}],"sharedSources":[],"slug":"mecp2-related-severe-neonatal-encephalopathy","sourceDocuments":[{"name":"MECP2-related severe neonatal encephalopathy","reviewed":"2011-10","sections":{"causes":{"fetchedAt":"2026-10-20T20:23:10.736792+00:00","label":"Causes","pageSha256":"61fccf7b8bbf794db73bf5e35724c410f9420e89658d2c2e8e7a113b7e963283","sourceUrl":"https://medlineplus.gov/genetics/condition/mecp2-related-severe-neonatal-encephalopathy/#causes","status":"available"}},"source_release":"2026-10-01","url":"https://medlineplus.gov/genetics/condition/mecp2-related-severe-neonatal-encephalopathy"}],"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":"MECP2-related severe neonatal encephalopathy"},"schemaVersion":1}