X-linked adrenoleukodystrophy (X-ALD) is a genetic disorder that occurs primarily in males. It mainly affects the nervous system and the adrenal glands, which are small glands located on top of each kidney. In this disorder, the fatty covering (myelin) that insulates nerves in the brain and spinal cord is prone to deterioration (demyelination), which reduces the ability of the nerves to relay information to the brain. In addition, damage to the outer layer of the adrenal glands (adrenal cortex) causes a shortage of certain hormones (adrenocortical insufficiency). Adrenocortical insufficiency may cause weakness, weight loss, skin changes, vomiting, and coma. Mutations in the ABCD1 gene cause X-linked adrenoleukodystrophy. The ABCD1 gene provides instructions for producing the adrenoleukodystrophy protein (ALDP), which is involved in transporting certain fat molecules called very long-chain fatty acids (VLCFAs) into peroxisomes. Peroxisomes are small sacs within cells that process many types of molecules, including VLCFAs.ABCD1 gene mutations result in a shortage (deficiency) of ALDP. When this protein is lacking, the transport and subsequent breakdown of VLCFAs is disrupted, causing abnormally high levels of these fats in the body. The accumulation of VLCFAs may be toxic to the adrenal cortex and myelin. Research suggests that the accumulation of VLCFAs triggers an inflammatory response in the brain, which could lead to the breakdown of myelin. The destruction of these tissues leads to the signs and symptoms of X-linked adrenoleukodystrophy.
| Condition:1 | X-linked Adrenoleukodystrophy |
|---|---|
| Abbreviation:1 | X-ALD |
| Category:2 | Core |
| SNOMED CT Code:3 |
65389002—Adrenoleukodystrophy disorder
UMLS CUI:4C0162309
|
| ICD-9-CM Code:5 |
277.9—Peroxisomal disorders
|
| ICD-10-CM Code:6 |
E71.522—Adrenomyeloneuropathy
E71.520—Childhood cerebral X-linked
adrenoleukodystrophy
E71.528—Other X-linked adrenoleukodystrophy
E71.529—X-linked adrenoleukodystrophy
unspecified type
|
These measurements are associated with the condition:
| LOINC Long Common Name9 | Analyte Short Name10 |
LOINC Number11 |
Units12 |
|---|---|---|---|
| ABCD1 gene mutations found [Identifier] in Blood or Tissue by Molecular genetics method Nominal | ABCD1 | 79568-2 | Answer list |
| Lysophosphatidylcholine(26:0) [Moles/volume] in Dried blood spot | C26:0-LPC | 79321-6 | umol/L |
| Lysophosphatidylcholine(26:0) [Moles/volume] in Dried blood spot by LC/MS/MS | C26:0-LPC-HPLC | 79567-4 | umol/L |
Additional information is available from Genetics Home Reference13 and from the Online Mendelian Inheritance in Man (OMIM®)14:
(OMIM 300100)Legend
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® Code — Systematized 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 Code — International 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 Code — International 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 Catalyse.
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
Resource, an international collaboration.
LOINC Long Common Name — derived by the Logical Observation
Identifiers Names and Codes (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 Codes (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 Measure (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 http://ghr.nlm.nih.gov/.
OMIM — Online Mendelian Inheritance in Man® 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.