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.
"},"coverage":{"countRecords":0,"emptyColumnKeys":[],"hpoRelease":"2026-06-23","narrativeSourceChanges":[],"records":5,"sourceGroups":{"omim":5,"orphanet":0,"published":0}},"features":[{"hpoId":"HP:0006934","label":"Congenital nystagmus","primary":false},{"hpoId":"HP:0000666","label":"Horizontal nystagmus","primary":false},{"hpoId":"HP:0032037","label":"Mildly reduced visual acuity","primary":false},{"hpoId":"HP:0012043","label":"Pendular nystagmus","primary":false},{"hpoId":"HP:0007663","label":"Reduced visual acuity","primary":false}],"ledeHtml":"X-linked infantile nystagmus is a condition characterized by abnormal eye movements. Nystagmus is a term that refers to involuntary side-to-side, up-and-down, or circular movements of the eyes. In people with X-linked infantile nystagmus, the movements are typically side-to-side. In individuals with this condition, nystagmus is present at birth or develops within the first six months of life.","mondoId":"MONDO:0010693","records":[{"frequencyKind":"reported","key":"1905b5e67b4c36cdf8e084d79bc8e99deba7709081c50afde07c39c26b60ff05","raw":{"aspect":"P","body_system":"eye","disease_id":"OMIM:310700","disease_name":"Nystagmus 1, congenital, X-linked","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0032037","is_excluded":false,"label":"Mildly reduced visual acuity","onset_id":null,"reference":"OMIM:310700","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"21787bba84833d4df013a053de15ae9ce83aca61f3e43906863e2ec24f66df52","raw":{"aspect":"P","body_system":"eye","disease_id":"OMIM:310700","disease_name":"Nystagmus 1, congenital, X-linked","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0006934","is_excluded":false,"label":"Congenital nystagmus","onset_id":null,"reference":"OMIM:310700","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"926fd47ca9f324df5bc3445f34e9e14edc8401bbca5890c29e61699b4e0e51e9","raw":{"aspect":"P","body_system":"eye","disease_id":"OMIM:310700","disease_name":"Nystagmus 1, congenital, X-linked","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0012043","is_excluded":false,"label":"Pendular nystagmus","onset_id":null,"reference":"OMIM:310700","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"9b118cabcc7244937db179b708752dc14ff857771d07671e419152545f65df2e","raw":{"aspect":"P","body_system":"eye","disease_id":"OMIM:310700","disease_name":"Nystagmus 1, congenital, X-linked","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0007663","is_excluded":false,"label":"Reduced visual acuity","onset_id":null,"reference":"OMIM:310700","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"a0897724e88a310c8a414b8184116941c9505b1cc16e36d1082eaa3defd4c1a9","raw":{"aspect":"P","body_system":"eye","disease_id":"OMIM:310700","disease_name":"Nystagmus 1, congenital, X-linked","evidence":"IEA","frequency_raw":null,"hpo_id":"HP:0000666","is_excluded":false,"label":"Horizontal nystagmus","onset_id":null,"reference":"OMIM:310700","source_release":"2026-06-23"},"sourceGroups":["omim"]}],"referenceLabels":{},"references":{"causeHtml":"","identityNote":"MONDO cross-references identify native condition entries. Ancestor membership does not transfer phenotype values between groups.","importantHtml":""},"sections":[{"bodyHtml":"Variants (also called mutations) in the FRMD7 gene cause X-linked infantile nystagmus. The FRMD7 gene provides instructions for making a protein whose exact function is unknown. This protein is found mostly in areas of the brain that control eye movement and in the light-sensitive tissue at the back of the eye (retina). Research suggests that FRMD7 gene variants cause nystagmus by disrupting the development of certain nerve cells in the brain and retina.
In some people with X-linked infantile nystagmus, no variant in the FRMD7 gene has been found. The genetic cause of the disorder is unknown in these individuals. Researchers believe that variants in at least one other gene, which has not been identified, can cause this disorder. Nystagmus can also occur in people with other X-linked eye conditions, such as X-linked ocular albinism. Such cases are caused by changes in genes associated with the particular condition.
","key":"forms","title":"What causes X-linked infantile nystagmus?"},{"bodyHtml":"The abnormal eye movements may worsen when an affected person is feeling anxious or tries to stare directly at an object. Some affected individuals will experience involuntary changes in the direction of their eye movements (periodic alternating nystagmus). The severity of nystagmus varies, even among affected individuals within the same family. Sometimes, affected individuals will turn or tilt their head to compensate for the irregular eye movements. Individuals with X-linked infantile nystagmus may have other eye abnormalities. For example, the region at the back of the eye responsible for sharp central vision may be underdeveloped (foveal hypoplasia).
Source: MedlinePlus Genetics
","key":"overview","title":"Condition overview"}],"sharedSources":[],"slug":"x-linked-infantile-nystagmus","sourceDocuments":[{"name":"X-linked infantile nystagmus","reviewed":"2023-09","sections":{"causes":{"fetchedAt":"2026-10-20T20:25:57.687781+00:00","label":"Causes","pageSha256":"eb15a47aefe88dcd2dbc0c8466b7d0b6de555828701facc88d75e2fe429fcf2a","sourceUrl":"https://medlineplus.gov/genetics/condition/x-linked-infantile-nystagmus/#causes","status":"available"}},"source_release":"2026-10-01","url":"https://medlineplus.gov/genetics/condition/x-linked-infantile-nystagmus"}],"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":"X-linked infantile nystagmus"},"schemaVersion":1}