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":4,"emptyColumnKeys":[],"hpoRelease":"2026-06-23","narrativeSourceChanges":[],"records":6,"sourceGroups":{"omim":2,"orphanet":0,"published":4}},"features":[{"hpoId":"HP:0012236","label":"Elevated sweat chloride","primary":false},{"hpoId":"HP:0001508","label":"Failure to thrive","primary":false},{"hpoId":"HP:0011968","label":"Feeding difficulties","primary":false},{"hpoId":"HP:0002153","label":"Hyperkalemia","primary":false},{"hpoId":"HP:0004906","label":"Hypernatremic dehydration","primary":false},{"hpoId":"HP:0002902","label":"Hyponatremia","primary":false}],"ledeHtml":"Isolated hyperchlorhidrosis is characterized by the excessive loss of salt (sodium chloride or NaCl) in sweat. In particular, "hyperchlorhidrosis" refers to the high levels of chloride found in sweat, although both sodium and chloride are released. Because the salt is abnormally released from the body in sweat, there are lower than normal levels of sodium in fluids inside the body (hyponatremia). Most infants with isolated hyperchlorhidrosis experience one or more episodes of dehydration with low levels of sodium in the blood (hyponatremic dehydration), which can require hospitalization. These episodes typically follow a mild illness that causes vomiting or diarrhea. Affected infants also have poor feeding and an inability to grow and gain weight at the expected rate (failure to thrive). By early childhood, though, weight and height usually catch up to normal, although the abnormal loss of salt still remains. These individuals may still experience dangerous hyponatremia when they sweat excessively, for example in warm temperatures or when exercising.","mondoId":"MONDO:0007747","records":[{"frequencyKind":"count","key":"176f51ace913a8fa2d3835800638d9001bcb246dd2dc7a027a2899371f71df43","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:143860","disease_name":"Hyperchlorhidrosis, isolated","evidence":"PCS","frequency_raw":"7/7","hpo_id":"HP:0012236","is_excluded":false,"label":"Elevated sweat chloride","onset_id":null,"reference":"PMID:21035102","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"4a51e4c189e852be8af3daac46854fcc39425e03817e39febea5e2641db1909a","raw":{"aspect":"P","body_system":"digestive","disease_id":"OMIM:143860","disease_name":"Hyperchlorhidrosis, isolated","evidence":"PCS","frequency_raw":"7/7","hpo_id":"HP:0011968","is_excluded":false,"label":"Feeding difficulties","onset_id":null,"reference":"PMID:21035102","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"reported","key":"845ad2f6e7d860ff646371c808d806d5d86ecaf345c248f41fb73bcb04a5ccc1","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:143860","disease_name":"Hyperchlorhidrosis, isolated","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0002902","is_excluded":false,"label":"Hyponatremia","onset_id":null,"reference":"OMIM:143860","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"reported","key":"89931956ce6ca405b39100c32d26cca754cfc482458a2af2a9719e89e7bfc21d","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:143860","disease_name":"Hyperchlorhidrosis, isolated","evidence":"TAS","frequency_raw":null,"hpo_id":"HP:0002153","is_excluded":false,"label":"Hyperkalemia","onset_id":null,"reference":"OMIM:143860","source_release":"2026-06-23"},"sourceGroups":["omim"]},{"frequencyKind":"count","key":"94e1f795bba6761d60a72743d3ed3eeb9ec6fb27ea18f270b9c2784721537a7e","raw":{"aspect":"P","body_system":"growth","disease_id":"OMIM:143860","disease_name":"Hyperchlorhidrosis, isolated","evidence":"PCS","frequency_raw":"7/7","hpo_id":"HP:0001508","is_excluded":false,"label":"Failure to thrive","onset_id":null,"reference":"PMID:21035102","source_release":"2026-06-23"},"sourceGroups":["published"]},{"frequencyKind":"count","key":"e68b3c05dc9fbfcad2b75d57f4c43c8cfc05d652c10cbb4b536ba17fec2d79e7","raw":{"aspect":"P","body_system":"metabolic","disease_id":"OMIM:143860","disease_name":"Hyperchlorhidrosis, isolated","evidence":"PCS","frequency_raw":"5/7","hpo_id":"HP:0004906","is_excluded":false,"label":"Hypernatremic dehydration","onset_id":null,"reference":"PMID:21035102","source_release":"2026-06-23"},"sourceGroups":["published"]}],"referenceLabels":{},"references":{"causeHtml":"","identityNote":"MONDO cross-references identify native condition entries. Ancestor membership does not transfer phenotype values between groups.","importantHtml":""},"sections":[{"bodyHtml":"Isolated hyperchlorhidrosis is caused by a mutation in the CA12 gene. This gene provides instructions for making a protein called carbonic anhydrase 12 (CA 12), which belongs to a family of related proteins known as carbonic anhydrases. These proteins carry out a chemical reaction that involves the molecules carbon dioxide and water and produces a negatively charged bicarbonate molecule (bicarbonate ion) and a positively charged hydrogen atom (known as a proton). The presence of protons and bicarbonate affect the relative acidity (pH) of cells, which is important for several cellular processes, including the transport of salt into and out of cells. Researchers suggest that by regulating cellular pH in the sweat glands, CA 12 is able to control the amount of salt released in sweat.
The CA12 gene mutation involved in isolated hyperchlorhidrosis leads to reduction of CA 12 protein function. Researchers speculate that the altered CA 12 is less able to regulate pH, and it loses its ability to control how much salt is released in sweat, leading to hyperchlorhidrosis.
","key":"forms","title":"What causes Isolated hyperchlorhidrosis?"},{"bodyHtml":"While hyperchlorhidrosis can occur as one of several features of other conditions, such as cystic fibrosis, people with isolated hyperchlorhidrosis do not have the additional signs and symptoms of these other conditions.
Source: MedlinePlus Genetics
","key":"overview","title":"Condition overview"}],"sharedSources":[],"slug":"isolated-hyperchlorhidrosis","sourceDocuments":[{"name":"Isolated hyperchlorhidrosis","reviewed":"2014-05","sections":{"causes":{"fetchedAt":"2026-10-20T20:22:32.598641+00:00","label":"Causes","pageSha256":"51e879a4ed2a78836ed73665e706eb41ccb224d232cfc48791509337f030f6e5","sourceUrl":"https://medlineplus.gov/genetics/condition/isolated-hyperchlorhidrosis/#causes","status":"available"}},"source_release":"2026-10-01","url":"https://medlineplus.gov/genetics/condition/isolated-hyperchlorhidrosis"}],"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":"Isolated hyperchlorhidrosis"},"schemaVersion":1}