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3-methylglutaconic aciduria, type VIIB(MGCA7B)

MedGen UID:
1810214
Concept ID:
C5676893
Disease or Syndrome
Synonyms: 3-methylglutaconic aciduria with cataracts, neurologic involvement and neutropenia; 3-methylglutaconic aciduria, type VII, with cataracts, neurologic involvement and neutropenia; MGCA7B
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): CLPB (11q13.4)
 
Monarch Initiative: MONDO:0014561
OMIM®: 616271
Orphanet: ORPHA445038

Disease characteristics

Excerpted from the GeneReview: CLPB Deficiency
CLPB (caseinolytic peptidase B) deficiency is characterized by neurologic involvement and neutropenia, which can range from severe to mild. In severe CLPB deficiency, death usually occurs at a few months of age due to significant neonatal neurologic involvement (hyperekplexia or absence of voluntary movements, hypotonia or hypertonia, swallowing problems, respiratory insufficiency, and epilepsy) and severe neutropenia associated with life-threatening infections. Individuals with moderate CLPB deficiency present with neurologic abnormalities in infancy including hypotonia and feeding problems, and develop spasticity, a progressive movement disorder (ataxia, dystonia, and/or dyskinesia), epilepsy, and intellectual disability. Neutropenia is variable, but not life threatening. In those with mild CLPB deficiency there is no neurologic involvement, intellect is normal, neutropenia is mild and intermittent, and life expectancy is normal. [from GeneReviews]
Authors:
Saskia B Wortmann  |  Ron A Wevers   view full author information

Additional descriptions

From OMIM
3-Methylglutaconic aciduria (MGCA7) is an inborn error of metabolism characterized primarily by increased levels of 3-methylglutaconic acid (3-MGA) associated with variable neurologic deficits and neutropenia. The phenotype is highly variable: most patients have infantile onset of a severe progressive encephalopathy with various movement abnormalities and delayed psychomotor development, although rare patients with normal neurologic development have been reported. Other common variable features include cataracts, seizures, recurrent infections due to neutropenia, and brain imaging abnormalities (summary by Wortmann et al., 2015 and Saunders et al., 2015). For a general phenotypic description and a discussion of genetic heterogeneity of 3-methylglutaconic aciduria, see MGCA1 (250950).  http://www.omim.org/entry/616271
From MedlinePlus Genetics
CLPB deficiency is a rare disorder characterized by neurological problems and a shortage of infection-fighting white blood cells (neutropenia). Signs and symptoms of the condition develop by early childhood, and their severity varies widely among affected individuals.

In the most severely affected individuals, features of CLPB deficiency are apparent in infancy and sometimes at birth. Affected babies have serious neurological problems, which can include an exaggerated startle reaction (hyperekplexia) to unexpected stimuli such as loud noises, reduced movement, muscle tone that is either decreased (hypotonia) or increased (hypertonia), swallowing problems, difficulty breathing, and recurrent seizures (epilepsy). These babies may also have movement abnormalities, such as difficulty coordinating movements (ataxia), involuntary tensing of the muscles (dystonia), or uncontrolled movements of the body (dyskinesia). In addition, these babies have recurrent, life-threatening infections due to severe neutropenia. Affected individuals are at risk of developing a blood cell disorder called myelodysplastic syndrome or a form of blood cancer called leukemia. Because of their severe health problems, affected infants usually live only a few weeks or months.

Moderately affected individuals have neurological problems similar to those described above, although they are less severe. They include hypotonia, muscle stiffness (spasticity), and movement abnormalities. Other features of moderate CLPB deficiency include epilepsy and mild to severe intellectual disability. Neutropenia in these individuals can lead to recurrent infections, although they are not life-threatening.

Mildly affected individuals have no neurological problems, and although they have neutropenia, it does not increase the risk of infections. Some people with mild CLPB deficiency develop deposits of calcium in the kidneys (nephrocalcinosis) or kidney (renal) cysts.

Many people with mild, moderate, or severe CLPB deficiency have clouding of the lenses of the eyes (cataracts) from birth (congenital) or beginning in infancy.

CLPB deficiency is associated with increased levels of a substance called 3-methylglutaconic acid in the urine (3-methylglutaconic aciduria). This abnormality, which provides a clue to the diagnosis, does not appear to cause any health problems.  https://medlineplus.gov/genetics/condition/clpb-deficiency

Clinical features

From HPO
3-Methylglutaconic aciduria
MedGen UID:
777186
Concept ID:
C3696376
Disease or Syndrome
An increased amount of 3-methylglutaconic acid in the urine.
Rhizomelia
MedGen UID:
357122
Concept ID:
C1866730
Congenital Abnormality
Disproportionate shortening of the proximal segment of limbs (i.e. the femur and humerus).
Brachioradialis areflexia
MedGen UID:
1784718
Concept ID:
C5539438
Finding
Inability to elicit brachioradialis tendon reflex.
Congestive heart failure
MedGen UID:
9169
Concept ID:
C0018802
Disease or Syndrome
The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction.
Fetal growth restriction
MedGen UID:
4693
Concept ID:
C0015934
Pathologic Function
An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.
Growth delay
MedGen UID:
99124
Concept ID:
C0456070
Pathologic Function
A deficiency or slowing down of growth pre- and postnatally.
Tube feeding
MedGen UID:
8641
Concept ID:
C0014327
Therapeutic or Preventive Procedure
Feeding problem necessitating food and nutrient delivery via a tube.
Feeding difficulties
MedGen UID:
65429
Concept ID:
C0232466
Finding
Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
Hepatic steatosis
MedGen UID:
398225
Concept ID:
C2711227
Disease or Syndrome
Steatosis is a term used to denote lipid accumulation within hepatocytes.
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).
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.
Myoclonus
MedGen UID:
10234
Concept ID:
C0027066
Finding
Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Tremor
MedGen UID:
21635
Concept ID:
C0040822
Sign or Symptom
An unintentional, oscillating to-and-fro muscle movement about a joint axis.
Choreoathetosis
MedGen UID:
39313
Concept ID:
C0085583
Disease or Syndrome
Involuntary movements characterized by both athetosis (inability to sustain muscles in a fixed position) and chorea (widespread jerky arrhythmic movements).
Opisthotonus
MedGen UID:
56246
Concept ID:
C0151818
Sign or Symptom
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.
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.
Cerebellar atrophy
MedGen UID:
196624
Concept ID:
C0740279
Disease or Syndrome
Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.
Increased CSF lactate
MedGen UID:
257904
Concept ID:
C1167918
Finding
Increased concentration of lactate in the cerebrospinal fluid.
Developmental regression
MedGen UID:
324613
Concept ID:
C1836830
Disease or Syndrome
Loss of developmental skills, as manifested by loss of developmental milestones.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.
Hyperkinetic movements
MedGen UID:
854367
Concept ID:
C3887506
Disease or Syndrome
Motor hyperactivity with excessive movement of muscles of the body as a whole.
Thrombocytopenia
MedGen UID:
52737
Concept ID:
C0040034
Disease or Syndrome
A reduction in the number of circulating thrombocytes.
Bone marrow maturation arrest
MedGen UID:
549798
Concept ID:
C0302173
Cell or Molecular Dysfunction
Interruption of the procecss of diffferentiation of hematopoietic cells in the bone marrow, manifested by an increased proportion of immature cells in the bone marrow.
Prolonged prothrombin time
MedGen UID:
208879
Concept ID:
C0853225
Finding
Increased time to coagulation in the prothrombin time test, which is a measure of the extrinsic pathway of coagulation. The results of the prothrombin time test are often expressed in terms of the International normalized ratio (INR), which is calculated as a ratio of the patient's prothrombin time (PT) to a control PT standardized for the potency of the thromboplastin reagent developed by the World Health Organization (WHO) using the formula
Abnormal bleeding
MedGen UID:
264316
Concept ID:
C1458140
Pathologic Function
An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects.
Micrognathia
MedGen UID:
44428
Concept ID:
C0025990
Congenital Abnormality
Developmental hypoplasia of the mandible.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Trismus
MedGen UID:
21671
Concept ID:
C0041105
Disease or Syndrome
Limitation in the ability to open the mouth.
Flexion contracture
MedGen UID:
83069
Concept ID:
C0333068
Anatomical Abnormality
A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints.
Neonatal hypotonia
MedGen UID:
412209
Concept ID:
C2267233
Disease or Syndrome
Muscular hypotonia (abnormally low muscle tone) manifesting in the neonatal period.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Respiratory distress
MedGen UID:
96907
Concept ID:
C0476273
Sign or Symptom
Respiratory distress is objectively observable as the physical or emotional consequences from the experience of dyspnea. The physical presentation of respiratory distress is generally referred to as labored breathing, while the sensation of respiratory distress is called shortness of breath or dyspnea.
Recurrent pneumonia
MedGen UID:
195802
Concept ID:
C0694550
Disease or Syndrome
An increased susceptibility to pneumonia as manifested by a history of recurrent episodes of pneumonia.
Leukopenia
MedGen UID:
6073
Concept ID:
C0023530
Disease or Syndrome
An abnormal decreased number of leukocytes in the blood.
Recurrent infections
MedGen UID:
65998
Concept ID:
C0239998
Finding
Increased susceptibility to infections.
Neutropenia
MedGen UID:
163121
Concept ID:
C0853697
Finding
An abnormally low number of neutrophils in the peripheral blood.
Dehydration
MedGen UID:
8273
Concept ID:
C0011175
Disease or Syndrome
A condition resulting from the excessive loss of water from the body. It is usually caused by severe diarrhea, vomiting or diaphoresis.
Neonatal hypoglycemia
MedGen UID:
57646
Concept ID:
C0158986
Finding
Blood glucose concentration below the lower limit of established reference ranges in a newborn.
Increased circulating lactate concentration
MedGen UID:
332209
Concept ID:
C1836440
Finding
Abnormally increased level of blood lactate (2-hydroxypropanoic acid). Lactate is produced from pyruvate by lactate dehydrogenase during normal metabolism. The terms lactate and lactic acid are often used interchangeably but lactate (the component measured in blood) is strictly a weak base whereas lactic acid is the corresponding acid. Lactic acidosis is often used clinically to describe elevated lactate but should be reserved for cases where there is a corresponding acidosis (pH below 7.35).
Bulbous nose
MedGen UID:
66013
Concept ID:
C0240543
Finding
Increased volume and globular shape of the anteroinferior aspect of the nose.
Periorbital fullness
MedGen UID:
1710990
Concept ID:
C4760994
Finding
Increase in periorbital soft tissue.
Polyhydramnios
MedGen UID:
6936
Concept ID:
C0020224
Pathologic Function
The presence of excess amniotic fluid in the uterus during pregnancy.
Decreased fetal movement
MedGen UID:
68618
Concept ID:
C0235659
Finding
An abnormal reduction in quantity or strength of fetal movements.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
Cataract
MedGen UID:
39462
Concept ID:
C0086543
Disease or Syndrome
A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.
Zonular cataract
MedGen UID:
350517
Concept ID:
C1861821
Disease or Syndrome
Zonular cataracts are defined to be cataracts that affect specific regions of the lens.

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