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3-methylglutaconic aciduria type 1(MGA1; MGCA1)

MedGen UID:
90994
Concept ID:
C0342727
Disease or Syndrome
Synonyms: 3 alpha methylglutaconic aciduria type I; 3 methylglutaconic aciduria type I; 3 methylglutaconyl CoA hydratase deficiency; 3MG CoA hydratase deficiency; MGA type I
SNOMED CT: 3-Methylglutaconic aciduria type 1 (237951008); 3-Methylglutaconyl-CoA hydratase deficiency with 3-methylglutaconic acid (237951008)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): AUH (9q22.31)
 
Monarch Initiative: MONDO:0009610
OMIM®: 250950
Orphanet: ORPHA67046

Definition

3-methylglutaconyl-CoA hydratase deficiency is an inherited condition that causes neurological problems. Beginning in infancy to early childhood, children with this condition often have delayed development of mental and motor skills (psychomotor delay), speech delay, involuntary muscle cramping (dystonia), and spasms and weakness of the arms and legs (spastic quadriparesis). Affected individuals can also have optic atrophy, which is the breakdown (atrophy) of nerve cells that carry visual information from the eyes to the brain.

In some cases, signs and symptoms of 3-methylglutaconyl-CoA hydratase deficiency begin in adulthood, often in a person's twenties or thirties. These individuals have damage to a type of brain tissue called white matter (leukoencephalopathy). This damage likely contributes to progressive problems with speech (dysarthria), difficulty coordinating movements (ataxia), stiffness (spasticity), optic atrophy, and a decline in intellectual function (dementia).

Affected individuals who show symptoms of 3-methylglutaconyl-CoA hydratase deficiency in childhood often go on to develop leukoencephalopathy and other neurological problems in adulthood.

All people with 3-methylglutaconyl-CoA hydratase deficiency accumulate large amounts of a substance called 3-methylglutaconic acid in their body fluids. As a result, they have elevated levels of acid in their blood (metabolic acidosis) and excrete large amounts of acid in their urine (aciduria). 3-methylglutaconyl-CoA hydratase deficiency is one of a group of metabolic disorders that can be diagnosed by the presence of increased levels 3-methylglutaconic acid in urine (3-methylglutaconic aciduria). People with 3-methylglutaconyl-CoA hydratase deficiency also have high urine levels of another acid called 3-methylglutaric acid. [from MedlinePlus Genetics]

Clinical features

From HPO
Urinary incontinence
MedGen UID:
22579
Concept ID:
C0042024
Finding
Loss of the ability to control the urinary bladder leading to involuntary urination.
3-Methylglutaconic aciduria
MedGen UID:
777186
Concept ID:
C3696376
Disease or Syndrome
An increased amount of 3-methylglutaconic acid in the urine.
Failure to thrive
MedGen UID:
746019
Concept ID:
C2315100
Disease or Syndrome
Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.
Athetosis
MedGen UID:
2115
Concept ID:
C0004158
Disease or Syndrome
A slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture. Athetosis involves continuous smooth movements that appear random and are not composed of recognizable sub-movements or movement fragments. In contrast to chorea, in athetosis, the same regions of the body are repeatedly involved. Athetosis may worsen with attempts at movement of posture, but athetosis can also occur at rest.
Cerebellar ataxia
MedGen UID:
849
Concept ID:
C0007758
Disease or Syndrome
Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).
Febrile seizure (within the age range of 3 months to 6 years)
MedGen UID:
3232
Concept ID:
C0009952
Disease or Syndrome
A febrile seizure is any type of seizure (most often a generalized tonic-clonic seizure) occurring with fever (at least 38 degrees Celsius) but in the absence of central nervous system infection, severe metabolic disturbance or other alternative precipitant in children between the ages of 3 months and 6 years.
Dysarthria
MedGen UID:
8510
Concept ID:
C0013362
Mental or Behavioral Dysfunction
Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.
Dystonic disorder
MedGen UID:
3940
Concept ID:
C0013421
Sign or Symptom
An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Self-mutilation
MedGen UID:
19925
Concept ID:
C0036601
Injury or Poisoning
Deliberate harm to one's body resulting in tissue damage, without a conscious intent to die.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
Short attention span
MedGen UID:
82652
Concept ID:
C0262630
Finding
Reduced attention span characterized by distractibility and impulsivity.
Leukoencephalopathy
MedGen UID:
78722
Concept ID:
C0270612
Disease or Syndrome
This term describes abnormality of the white matter of the cerebrum resulting from damage to the myelin sheaths of nerve cells.
Cognitive impairment
MedGen UID:
90932
Concept ID:
C0338656
Mental or Behavioral Dysfunction
Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering.
Spastic tetraplegia
MedGen UID:
98433
Concept ID:
C0426970
Disease or Syndrome
Spastic paralysis affecting all four limbs.
Delayed speech and language development
MedGen UID:
105318
Concept ID:
C0454644
Finding
A degree of language development that is significantly below the norm for a child of a specified age.
Dementia
MedGen UID:
99229
Concept ID:
C0497327
Mental or Behavioral Dysfunction
A loss of global cognitive ability of sufficient amount to interfere with normal social or occupational function. Dementia represents a loss of previously present cognitive abilities, generally in adults, and can affect memory, thinking, language, judgment, and behavior.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Abnormal cerebral white matter morphology
MedGen UID:
181756
Concept ID:
C0948163
Pathologic Function
An abnormality of the cerebral white matter.
Motor delay
MedGen UID:
381392
Concept ID:
C1854301
Finding
A type of Developmental delay characterized by a delay in acquiring motor skills.
Metabolic acidosis
MedGen UID:
65117
Concept ID:
C0220981
Pathologic Function
Metabolic acidosis (MA) is characterized by a fall in blood pH due to a reduction of serum bicarbonate concentration. This can occur as a result of either the accumulation of acids (high anion gap MA) or the loss of bicarbonate from the gastrointestinal tract or the kidney (hyperchloremic MA). By definition, MA is not due to a respirary cause.
Reduced tissue 3-methylglutaconyl-CoA hydratase activity
MedGen UID:
1052796
Concept ID:
CN377409
Finding
Activity of the mitochondrial enzyme 3-methylglutaconyl-CoA hydratase (EC 4.2.1.18) in tissues below the lower limit of normal. The activity can be measured in multiple tissues including culutured fibroblasts.
Optic atrophy
MedGen UID:
18180
Concept ID:
C0029124
Disease or Syndrome
Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy.

Recent clinical studies

Diagnosis

Tavasoli AR, Shervin Badv R, Zschocke J, Ashrafi MR, Rostami P
Brain Dev 2017 Sep;39(8):714-716. Epub 2017 Apr 21 doi: 10.1016/j.braindev.2017.04.007. PMID: 28438368
Arbelaez A, Castillo M, Stone J
Neuroradiology 1999 Dec;41(12):941-2. doi: 10.1007/s002340050871. PMID: 10639672

Supplemental Content

Table of contents

    Clinical resources

    Practice guidelines

    Curated

    • ACMG ACT, 2022
      American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Elevated C5-OH Acylcarnitine, Organic Acidemias, 2022
    • ACMG Algorithm, 2022
      American College of Medical Genetics and Genomics, Algorithm, Organic Acidemias: Elevated C5-OH, 2022

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