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HHH - Hyperornithinemia-Hyperammonemia-Homocitrullinuria syndrome - Condition Details

Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome (also known as ornithine translocase deficiency) is an inherited disorder that causes ammonia to accumulate in the blood. Because the nervous system is especially sensitive to the effects of excess ammonia, this condition causes lethargy, poor appetite, and poorly controlled breathing or body temperature. Some babies with this disorder may experience seizures or unusual body movements, or go into a coma. Complications may include developmental delay, learning disabilities, and spasticity. Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome is caused by mutations in the SLC25A15 gene; it has an autosomal recessive pattern of inheritance.

Names and Codes

Condition:1Hyperornithinemia-Hyperammonemia-Homocitrullinuria syndrome
30287008Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome
UMLS CUI:4C0268540
ICD-9-CM Code:5
270.6Disorders of urea cycle metabolism
ICD-10-CM Code:6
E72.4Disorders of ornithine metabolism

Affected Protein Names and Codes

Enzyme Commission Number:7
UniProt Number:8
Q9Y619External Web Site PolicyMitochondrial ornithine transporter 1

Analytes or Measurements

These measurements are associated with the condition:

LOINC Long Common Name9Analyte
Short Name10
Asparagine+Ornithine [Moles/volume] in Dried blood spotASN + ORN53155-8umol/L
Asparagine+Ornithine/Phenylalanine [Molar ratio] in Dried blood spot[ASN + ORN] / PHE53396-8{ratio}
Asparagine+Ornithine/Serine [Molar ratio] in Dried blood spot[ASN + ORN] / SER53395-0{ratio}
Homocitrulline [Moles/volume] in Dried blood spotHOMOCIT53158-2umol/L
Ornithine/Citrulline [Molar ratio] in Dried blood spotORN / CIT75215-4{ratio}

More Information

Additional information is available from Genetics Home Reference13 and from the Online Mendelian Inheritance in Man (OMIM®)14:



Condition Name and Abbreviation — curated by the NLM and selected from among the names used by the Advisory Committee on Heritable Disorders in Newborns and Children (Committee), National Newborn Screening Information System (NNSIS), the American College of Medical Genetics (ACMG), the HHS Office of the National Coordinator for Health Information Technology (ONC)/American Health Information Community (AHIC) Personalized Health Care Work Group, and input from the newborn screening community.


Category — based on the U.S. Department of Health and Human Services (HHS) Recommended Uniform Screening Panel. Conditions designated as "core" should be included in every newborn screening program, and "secondary" conditions are some of the disorders that may be detected during screening for a core disorder. Conditions classified as "other" are those that are screened for by some states but are not part of the Recommended Uniform Screening Panel.


SNOMED CT® CodeSystematized Nomenclature of Medicine — Clinical Terms code is assigned by the International Health Terminology Standards Development Organisation (IHTSDO). SNOMED CT is a concept-oriented clinical terminology that has been designated as a U.S. standard for electronic health information exchange. The Newborn Screening Coding and Terminology Guide uses some codes from the US Extension to SNOMED CT.


UMLS CUI — a concept unique identifier (CUI) assigned to every concept in the Unified Medical Language System (UMLS®).


ICD-9-CM CodeInternational Classification of Diseases, Ninth Revision, Clinical Modification code is assigned to diagnoses associated with hospital utilization in the U.S. It is a current US standard for use in administrative healthcare transactions. Although ICD-9-CM codes are fairly specific, in certain cases, the same ICD-9-CM code might apply to several disorders in the same group (e.g. amino acid disorders).


ICD-10-CM CodeInternational Classification of Diseases, Tenth Revision, Clinical Modification code. Although ICD-10-CM codes are fairly specific, in certain cases, the same ICD-10-CM code might apply to multiple related disorders.


Enzyme Commission (EC) Number — a unique identifier for the affected enzyme (if the affected protein is an enzyme); the EC number is assigned by the Recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the Nomenclature and Classification of Enzymes by the Reactions they CatalyseExternal Web Site Policy.


UniProt Number — a unique identifier assigned to all proteins, including enzymes, hemoglobin subunits, and immunoglobulin chains. The UniProt database is maintained by the Universal Protein ResourceExternal Web Site Policy, an international collaboration.


LOINC Long Common Name — derived by the Logical Observation Identifiers Names and CodesExternal Web Site Policy (LOINC®) Committee from the measurement's formal name by using conventional names for analytes and procedures. The long common name eliminates the parts of the formal name that are not needed to distinguish the test from related tests.


Analyte Short Name — an abbreviation for the analyte.


LOINC Number — the unique and permanent code assigned by the Logical Observation Identifiers Names and CodesExternal Web Site Policy (LOINC®) Committee to identify the test measurement. LOINC codes are unique for different test methods and different units of reporting to enable interoperability and comparison of results from different labs. LOINC is a U.S. government standard for electronic health information exchange of laboratory tests and other measurements in Interoperability Specifications produced by the Healthcare Information Technology Standards Panel (HITSP).


Units — what is being counted or measured, using the Unified Code for Units of MeasureExternal Web Site Policy (UCUM). Ratios whose units fully cancel each other are indicated by {Ratio}. UCUM is the US standard for reporting units in laboratory messages. Results that are not quantitative have either a link to the specific LOINC answer list for that analyte or appropriate text (such as "Pos or Neg" or "Specific alleles").


Genetics Home Reference — the National Library of Medicine's Web site for consumer-friendly information about genetic conditions and the genes or chromosomes related to those conditions. Visit Genetics Home Reference at


OMIMOnline Mendelian Inheritance in Man®External Web Site Policy is a comprehensive resource about human genes and genetic diseases. It focuses primarily on the relationship between genotype and phenotype. It is currently maintained by Johns Hopkins University.

Record created: December 19, 2008
Record last updated: August 26, 2014