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Aspartylglucosaminuria(AGU)

MedGen UID:
78649
Concept ID:
C0268225
Disease or Syndrome
Synonyms: AGA deficiency; AGU; Aspartylglucos-amidase (AGA) deficiency; Aspartylglucos-aminuria; Aspartylglycosaminuria; GLYCOASPARAGINASE; Glycosylasparaginase deficiency
SNOMED CT: Aspartylglycosylaminase deficiency (54954004); Aspartylglucosaminuria (54954004); Aspartylglycosaminuria (54954004); Aspartylglucosaminidase deficiency (54954004)
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): AGA (4q34.3)
 
HPO: HP:0012068
Monarch Initiative: MONDO:0008830
OMIM®: 208400
Orphanet: ORPHA93

Definition

Aspartylglucosaminuria (AGU) is a severe autosomal recessive lysosomal storage disorder that involves the central nervous system and causes skeletal abnormalities as well as connective tissue lesions. The most characteristic feature is progressive mental retardation. The disorder is caused by deficient activity of the lysosomal enzyme glycosylasparaginase, which results in body fluid and tissue accumulation of a series of glycoasparagines, i.e., glycoconjugates with an aspartylglucosamine moiety at the reducing end. AGU belongs to the group of disorders commonly referred to as the Finnish disease heritage (summary by Mononen et al., 1993 and Arvio and Arvio, 2002). [from OMIM]

Additional description

From MedlinePlus Genetics
Aspartylglucosaminuria is a condition that primarily affects mental functioning and movement. This conditions worsens over time. Infants with aspartylglucosaminuria appear healthy at birth, and development is typically normal throughout early childhood. Around the age of 2 or 3, affected children usually begin to have delayed speech, mild intellectual disability, and problems coordinating movements. Other features that develop in childhood include respiratory infections, a protrusion of organs through gaps in muscles (hernia), and a growth spurt resulting in a large head size (macrocephaly).

Intellectual disability and movement problems worsen in adolescence. Most people with this disorder lose much of the speech they have learned, and affected adults usually have only a few words in their vocabulary. Adults with aspartylglucosaminuria often have psychological disorders and may develop seizures.

People with aspartylglucosaminuria may also have bones that become progressively weak and prone to fracture (osteoporosis), an unusually large range of joint movement (hypermobility), and loose skin. Affected individuals tend to have a characteristic facial appearance that includes widely spaced eyes (ocular hypertelorism), small ears, and full lips. The nose is short and broad and the face is usually square-shaped. They often have poor oral health, including infections and gum disease (gingivitis). Children with this condition may be tall for their age, but lack of a growth spurt in puberty typically causes adults to be short with a small head size (microcephaly). Individuals with aspartylglucosaminuria usually survive into mid-adulthood.  https://medlineplus.gov/genetics/condition/aspartylglucosaminuria

Clinical features

From HPO
Aspartylglucosaminuria
MedGen UID:
78649
Concept ID:
C0268225
Disease or Syndrome
Aspartylglucosaminuria (AGU) is a severe autosomal recessive lysosomal storage disorder that involves the central nervous system and causes skeletal abnormalities as well as connective tissue lesions. The most characteristic feature is progressive mental retardation. The disorder is caused by deficient activity of the lysosomal enzyme glycosylasparaginase, which results in body fluid and tissue accumulation of a series of glycoasparagines, i.e., glycoconjugates with an aspartylglucosamine moiety at the reducing end. AGU belongs to the group of disorders commonly referred to as the Finnish disease heritage (summary by Mononen et al., 1993 and Arvio and Arvio, 2002).
Macroorchidism
MedGen UID:
224727
Concept ID:
C1263023
Finding
The presence of abnormally large testes.
Mitral regurgitation
MedGen UID:
7670
Concept ID:
C0026266
Disease or Syndrome
An abnormality of the mitral valve characterized by insufficiency or incompetence of the mitral valve resulting in retrograde leaking of blood through the mitral valve upon ventricular contraction.
Short stature
MedGen UID:
87607
Concept ID:
C0349588
Finding
A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).
Diarrhea
MedGen UID:
8360
Concept ID:
C0011991
Sign or Symptom
Abnormally increased frequency (usually defined as three or more) loose or watery bowel movements a day.
Hepatomegaly
MedGen UID:
42428
Concept ID:
C0019209
Finding
Abnormally increased size of the liver.
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.
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.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
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.
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.
Decreased prothrombin time
MedGen UID:
154375
Concept ID:
C0580413
Finding
Abnormally short 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
Pathologic fracture
MedGen UID:
42095
Concept ID:
C0016663
Pathologic Function
A pathologic fracture occurs when a bone breaks in an area that is weakened secondarily to another disease process such as tumor, infection, and certain inherited bone disorders. A pathologic fracture can occur without a degree of trauma required to cause fracture in healthy bone.
Hernia
MedGen UID:
6816
Concept ID:
C0019270
Finding
The protrusion of part of an organ or fibroadipose tissue through an abnormal opening.
Kyphosis
MedGen UID:
44042
Concept ID:
C0022821
Anatomical Abnormality
Exaggerated anterior convexity of the thoracic vertebral column.
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.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Spondylolisthesis
MedGen UID:
52470
Concept ID:
C0038016
Disease or Syndrome
Spondylolisthesis is defined as forward slipping of a vertebral body on the one below it. Spondylolysis is defined as a defect in the pars interarticularis without vertebral slipping (summary by Wiltse et al., 1975).
Spondylolysis
MedGen UID:
21294
Concept ID:
C0038018
Disease or Syndrome
Spondylolysis is an osseous defect of the pars interarticularis, thought to be a developmental or acquired stress fracture secondary to chronic low-grade trauma.
Brachycephaly
MedGen UID:
113165
Concept ID:
C0221356
Congenital Abnormality
An abnormality of skull shape characterized by a decreased anterior-posterior diameter. That is, a cephalic index greater than 81%. Alternatively, an apparently shortened anteroposterior dimension (length) of the head compared to width.
Delayed skeletal maturation
MedGen UID:
108148
Concept ID:
C0541764
Finding
A decreased rate of skeletal maturation. Delayed skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body.
Platyspondyly
MedGen UID:
335010
Concept ID:
C1844704
Finding
A flattened vertebral body shape with reduced distance between the vertebral endplates.
Joint hypermobility
MedGen UID:
336793
Concept ID:
C1844820
Finding
The capability that a joint (or a group of joints) has to move, passively and/or actively, beyond normal limits along physiological axes.
Beaking of vertebral bodies
MedGen UID:
341588
Concept ID:
C1856599
Finding
Anterior tongue-like protrusions of the vertebral bodies.
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Thickened calvaria
MedGen UID:
346823
Concept ID:
C1858452
Finding
The presence of an abnormally thick calvaria.
Hypoplastic frontal sinuses
MedGen UID:
349225
Concept ID:
C1859682
Finding
Underdevelopment of frontal sinus.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Dysostosis multiplex
MedGen UID:
1851010
Concept ID:
C5848292
Disease or Syndrome
Recurrent respiratory infections
MedGen UID:
812812
Concept ID:
C3806482
Finding
An increased susceptibility to respiratory infections as manifested by a history of recurrent respiratory infections.
Acne
MedGen UID:
152379
Concept ID:
C0702166
Disease or Syndrome
A skin condition in which there is an increase in sebum secretion by the pilosebaceous apparatus associated with open comedones (blackheads), closed comedones (whiteheads), and pustular nodules (papules, pustules, and cysts).
Neutropenia
MedGen UID:
163121
Concept ID:
C0853697
Finding
An abnormally low number of neutrophils in the peripheral blood.
Vacuolated lymphocytes
MedGen UID:
332307
Concept ID:
C1836855
Finding
The presence of clear, sharply defined vacuoles in the lymphocyte cytoplasm.
Abnormality of metabolism/homeostasis
MedGen UID:
867398
Concept ID:
C4021768
Finding
Reduced tissue aspartylglucosaminidase activity
MedGen UID:
1052734
Concept ID:
CN377405
Finding
Activity of aspartylglucosaminidase (AGA; EC 3.5.1.26) in the tissues below the lower limit of normal. AGA activity can be measured in multiple tissues including leukocytes and cultured fibroblasts.
Hoarse voice
MedGen UID:
5602
Concept ID:
C0019825
Sign or Symptom
Hoarseness refers to a change in the pitch or quality of the voice, with the voice sounding weak, very breathy, scratchy, or husky.
Macroglossia
MedGen UID:
44236
Concept ID:
C0024421
Disease or Syndrome
Increased length and width of the tongue.
Wide mouth
MedGen UID:
44238
Concept ID:
C0024433
Congenital Abnormality
Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective).
Depressed nasal bridge
MedGen UID:
373112
Concept ID:
C1836542
Finding
Posterior positioning of the nasal root in relation to the overall facial profile for age.
Thick lower lip vermilion
MedGen UID:
326567
Concept ID:
C1839739
Finding
Increased thickness of the lower lip, leading to a prominent appearance of the lower lip. The height of the vermilion of the lower lip in the midline is more than 2 SD above the mean. Alternatively, an apparently increased height of the vermilion of the lower lip in the frontal view (subjective).
Anteverted nares
MedGen UID:
326648
Concept ID:
C1840077
Finding
Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip).
Coarse facial features
MedGen UID:
335284
Concept ID:
C1845847
Finding
Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.
Broad face
MedGen UID:
349223
Concept ID:
C1859680
Finding
Bizygomatic (upper face) and bigonial (lower face) width greater than 2 standard deviations above the mean (objective); or an apparent increase in the width of the face (subjective).
Fabry disease
MedGen UID:
8083
Concept ID:
C0002986
Disease or Syndrome
Fabry disease is the most common of the lysosomal storage disorders and results from deficient activity of the enzyme alpha-galactosidase A (a-Gal A), leading to progressive lysosomal deposition of globotriaosylceramide and its derivatives in cells throughout the body. The classic form, occurring in males with less than 1% a-Gal A enzyme activity, usually has its onset in childhood or adolescence with periodic crises of severe pain in the extremities (acroparesthesia), the appearance of vascular cutaneous lesions (angiokeratomas), sweating abnormalities (anhidrosis, hypohidrosis, and rarely hyperhidrosis), characteristic corneal and lenticular opacities, and proteinuria. Gradual deterioration of renal function to end-stage renal disease (ESRD) usually occurs in men in the third to fifth decade. In middle age, most males successfully treated for ESRD develop cardiac and/or cerebrovascular disease, a major cause of morbidity and mortality. Heterozygous females typically have milder symptoms at a later age of onset than males. Rarely, females may be relatively asymptomatic throughout a normal life span or may have symptoms as severe as those observed in males with the classic phenotype. In contrast, late-onset forms occur in males with greater than 1% a-Gal A activity. Clinical manifestations include cardiac disease, which usually presents in the sixth to eighth decade with left ventricular hypertrophy, cardiomyopathy, arrhythmia, and proteinuria; renal failure, associated with ESRD but without the skin lesions or pain; or cerebrovascular disease presenting as stroke or transient ischemic attack.
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.

Conditions with this feature

Aspartylglucosaminuria
MedGen UID:
78649
Concept ID:
C0268225
Disease or Syndrome
Aspartylglucosaminuria (AGU) is a severe autosomal recessive lysosomal storage disorder that involves the central nervous system and causes skeletal abnormalities as well as connective tissue lesions. The most characteristic feature is progressive mental retardation. The disorder is caused by deficient activity of the lysosomal enzyme glycosylasparaginase, which results in body fluid and tissue accumulation of a series of glycoasparagines, i.e., glycoconjugates with an aspartylglucosamine moiety at the reducing end. AGU belongs to the group of disorders commonly referred to as the Finnish disease heritage (summary by Mononen et al., 1993 and Arvio and Arvio, 2002).

Professional guidelines

PubMed

Huang R, Cathey S, Pollard L, Wood T
Clin Chem 2018 Dec;64(12):1772-1779. Epub 2018 Sep 10 doi: 10.1373/clinchem.2018.289645. PMID: 30201803
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Recent clinical studies

Etiology

Naumchik BM, Gupta A, Flanagan-Steet H, Steet RA, Cathey SS, Orchard PJ, Lund TC
Cells 2020 Jun 5;9(6) doi: 10.3390/cells9061411. PMID: 32517081Free PMC Article
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Diagnosis

Hagemeijer MC, van den Bosch JC, Bongaerts M, Jacobs EH, van den Hout JMP, Oussoren E, Ruijter GJG
J Inherit Metab Dis 2023 Mar;46(2):206-219. Epub 2023 Feb 28 doi: 10.1002/jimd.12597. PMID: 36752951
Goodspeed K, Feng C, Laine M, Lund TC
J Child Neurol 2021 Apr;36(5):403-414. Epub 2021 Jan 13 doi: 10.1177/0883073820980904. PMID: 33439067
Arvio M, Mononen I
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Arvio P, Arvio M
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Therapy

Banning A, Schiff M, Tikkanen R
Biochim Biophys Acta Mol Basis Dis 2018 Mar;1864(3):668-675. Epub 2017 Dec 13 doi: 10.1016/j.bbadis.2017.12.014. PMID: 29247835
Banning A, Gülec C, Rouvinen J, Gray SJ, Tikkanen R
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Acta Neurol Scand 1993 May;87(5):342-4. doi: 10.1111/j.1600-0404.1993.tb04114.x. PMID: 8333236

Prognosis

Vargas-Díez E, Chabás A, Coll MJ, Sánchez-Pérez J, García-Díez A, Fernández-Herrera JM
Br J Dermatol 2002 Oct;147(4):760-4. doi: 10.1046/j.1365-2133.2002.04827.x. PMID: 12366426
Arvio P, Arvio M
Acta Paediatr 2002;91(3):255-7. doi: 10.1080/08035250252833842. PMID: 12022293
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J Inherit Metab Dis 1997 Nov;20(6):799-802. doi: 10.1023/a:1005371802085. PMID: 9427148
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Kelly TE
Clin Orthop Relat Res 1976 Jan-Feb;(114):116-33. PMID: 131015

Clinical prediction guides

Hagemeijer MC, van den Bosch JC, Bongaerts M, Jacobs EH, van den Hout JMP, Oussoren E, Ruijter GJG
J Inherit Metab Dis 2023 Mar;46(2):206-219. Epub 2023 Feb 28 doi: 10.1002/jimd.12597. PMID: 36752951
Harjunen EL, Laine M, Tikkanen R, Helenius P
J Inherit Metab Dis 2020 Mar;43(2):318-325. Epub 2019 Sep 8 doi: 10.1002/jimd.12159. PMID: 31415096
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Recent systematic reviews

Autti T, Joensuu R, Aberg L
Neuroradiology 2007 Jul;49(7):571-8. Epub 2007 Mar 3 doi: 10.1007/s00234-007-0220-6. PMID: 17334752

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