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Sialidosis type 2

MedGen UID:
924303
Concept ID:
C4282398
Disease or Syndrome
Synonyms: CHERRY RED SPOT--MYOCLONUS SYNDROME; Glycoprotein neuraminidase deficiency; Lipomucopolysaccharidosis; ML I; Mucolipidosis I; Mucolipidosis type 1; NEU 1 deficiency; NEU DEFICIENCY; Neuraminidase 1 deficiency; Neuraminidase deficiency; Sialidase deficiency; Sialidosis, type II
SNOMED CT: Neuraminidase deficiency (38795005); Deficiency of neuraminidase (124461006); Deficiency of sialidase (124461006); Neuroaminidase deficiency (38795005); Sialidase deficiency (38795005)
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): NEU1 (6p21.33)
 
Monarch Initiative: MONDO:0009738
OMIM®: 256550
Orphanet: ORPHA87876

Definition

Sialidosis is an autosomal recessive disorder characterized by the progressive lysosomal storage of sialylated glycopeptides and oligosaccharides caused by a deficiency of the enzyme neuraminidase. Common to the sialidoses is the accumulation and/or excretion of sialic acid (N-acetylneuraminic acid) covalently linked ('bound') to a variety of oligosaccharides and/or glycoproteins (summary by Lowden and O'Brien, 1979). The sialidoses are distinct from the sialurias in which there is storage and excretion of 'free' sialic acid, rather than 'bound' sialic acid; neuraminidase activity in sialuria is normal or elevated. Salla disease (604369) is a form of 'free' sialic acid disease. Classification Lowden and O'Brien (1979) provided a logical nosology of neuraminidase deficiency into sialidosis type I and type II. Type I is the milder form, also known as the 'normosomatic' type or the cherry red spot-myoclonus syndrome. Sialidosis type II is the more severe form with an earlier onset, and is also known as the 'dysmorphic' type. Type II has been subdivided into juvenile and infantile forms. Other terms for sialidosis type II are mucolipidosis I and lipomucopolysaccharidosis. [from OMIM]

Additional description

From MedlinePlus Genetics
The juvenile form has the least severe signs and symptoms of the different forms of sialidosis type II. Features of this condition usually appear in late childhood and may include mildly "coarse" facial features, mild bone abnormalities, cherry-red spots, myoclonus, intellectual disability, and dark red spots on the skin (angiokeratomas). The life expectancy of individuals with juvenile sialidosis type II varies depending on the severity of symptoms.

Infantile sialidosis type II shares some features with the congenital form, although the signs and symptoms are slightly less severe and begin within the first year of life. Features of the infantile form include hepatosplenomegaly, dysostosis multiplex, "coarse" facial features, short stature, and intellectual disability. As children with infantile sialidosis type II get older, they may develop myoclonus and cherry-red spots. Other signs and symptoms include hearing loss, overgrowth of the gums (gingival hyperplasia), and widely spaced teeth. Affected individuals may survive into childhood or adolescence.

Sialidosis type II, the more severe type of the disorder, is further divided into congenital, infantile, and juvenile forms. The features of congenital sialidosis type II can develop before birth. This form of sialidosis is associated with an abnormal buildup of fluid in the abdominal cavity (ascites) or widespread swelling before birth caused by fluid accumulation (hydrops fetalis). Affected infants may also have an enlarged liver and spleen (hepatosplenomegaly), abnormal bone development (dysostosis multiplex), and distinctive facial features that are often described as "coarse." As a result of these serious health problems, individuals with congenital sialidosis type II usually are stillborn or die soon after birth.

Sialidosis type I, also referred to as cherry-red spot myoclonus syndrome, is the less severe form of this condition. People with type I develop signs and symptoms of sialidosis in their teens or twenties. Initially, affected individuals experience problems walking (gait disturbance) and/or a loss of sharp vision (reduced visual acuity). Individuals with sialidosis type I also experience muscle twitches (myoclonus), difficulty coordinating movements (ataxia), leg tremors, and seizures. The myoclonus worsens over time, causing difficulty sitting, standing, or walking. People with sialidosis type I eventually require wheelchair assistance. Affected individuals have progressive vision problems, including impaired color vision or night blindness. An eye abnormality called a cherry-red spot, which can be identified with an eye examination, is characteristic of this disorder. Sialidosis type I does not affect intelligence or life expectancy.

Sialidosis is a severe inherited disorder that affects many organs and tissues, including the nervous system. This disorder is divided into two types, which are distinguished by the age at which symptoms appear and the severity of features.  https://medlineplus.gov/genetics/condition/sialidosis

Clinical features

From HPO
Proteinuria
MedGen UID:
10976
Concept ID:
C0033687
Finding
Increased levels of protein in the urine.
Increased urinary O-linked sialopeptides
MedGen UID:
373111
Concept ID:
C1836533
Finding
Excretion of peptides conjugated to sialic acid in the urine.
Urinary excretion of sialylated oligosaccharides
MedGen UID:
435893
Concept ID:
C2673302
Finding
Excretion of oligosaccharides conjugated to sialic acid in the urine.
Cardiomegaly
MedGen UID:
5459
Concept ID:
C0018800
Finding
Increased size of the heart, clinically defined as an increased transverse diameter of the cardiac silhouette that is greater than or equal to 50% of the transverse diameter of the chest (increased cardiothoracic ratio) on a posterior-anterior projection of a chest radiograph or a computed tomography.
Cardiomyopathy
MedGen UID:
209232
Concept ID:
C0878544
Disease or Syndrome
A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.
Cherry red spot of the macula
MedGen UID:
786046
Concept ID:
C2216370
Finding
Pallor of the perifoveal macula of the retina with appearance of a small circular reddish choroid shape as seen through the fovea centralis due to relative transparency of the macula.
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).
Ascites
MedGen UID:
416
Concept ID:
C0003962
Disease or Syndrome
Accumulation of fluid in the peritoneal cavity.
Hepatomegaly
MedGen UID:
42428
Concept ID:
C0019209
Finding
Abnormally increased size of the liver.
Sensorineural hearing loss disorder
MedGen UID:
9164
Concept ID:
C0018784
Disease or Syndrome
A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.
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.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Dysmetria
MedGen UID:
68583
Concept ID:
C0234162
Finding
A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements.
Slurred speech
MedGen UID:
65885
Concept ID:
C0234518
Finding
Abnormal coordination of muscles involved in speech.
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.
Inguinal hernia
MedGen UID:
6817
Concept ID:
C0019294
Finding
Protrusion of the contents of the abdominal cavity through the inguinal canal.
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.
Muscle weakness
MedGen UID:
57735
Concept ID:
C0151786
Finding
Reduced strength of muscles.
Muscular atrophy
MedGen UID:
892680
Concept ID:
C0541794
Pathologic Function
The presence of skeletal muscular atrophy (which is also known as amyotrophy).
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Epiphyseal stippling
MedGen UID:
349104
Concept ID:
C1859126
Finding
The presence of abnormal punctate (speckled, dot-like) calcifications in one or more epiphyses.
Dysostosis multiplex
MedGen UID:
1851010
Concept ID:
C5848292
Disease or Syndrome
Splenomegaly
MedGen UID:
52469
Concept ID:
C0038002
Finding
Abnormal increased size of the spleen.
Vacuolated lymphocytes
MedGen UID:
332307
Concept ID:
C1836855
Finding
The presence of clear, sharply defined vacuoles in the lymphocyte cytoplasm.
Bone-marrow foam cells
MedGen UID:
383940
Concept ID:
C1856560
Finding
The presence of foam cells in the bone marrow, generally demonstrated by bone-marrow aspiration or biopsy. Foam cells have a vacuolated appearance due to the presence of complex lipid deposits, giving them a foamy or soap-suds appearance.
Reduced tissue neuraminidase activity
MedGen UID:
1054044
Concept ID:
CN378263
Finding
Activity of neuraminidase (EC 3.2.1.18)in tissues below the lower limit of normal. The activity can be measured in multiple tissues including culutured fibroblasts. Neuraminidase is also known as lysosomal sialidase.
Facial edema
MedGen UID:
154241
Concept ID:
C0542571
Pathologic Function
Swelling due to an excessive accumulation of fluid in facial tissues.
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.
Hydrops fetalis
MedGen UID:
6947
Concept ID:
C0020305
Disease or Syndrome
The abnormal accumulation of fluid in two or more fetal compartments, including ascites, pleural effusion, pericardial effusion, and skin edema.
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.
Progressive visual loss
MedGen UID:
326867
Concept ID:
C1839364
Finding
A reduction of previously attained ability to see.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  

Professional guidelines

PubMed

Du YC, Ma LH, Li QF, Ma Y, Dong Y, Wu ZY
Orphanet J Rare Dis 2024 Sep 30;19(1):362. doi: 10.1186/s13023-024-03378-5. PMID: 39350194Free PMC Article
Wang L, Qiu YL, Xu HM, Zhu J, Li SJ, OuYang WX, Yang YF, Lu Y, Xie XB, Xing QH, Wang JS
Liver Int 2022 Feb;42(2):402-411. Epub 2021 Nov 29 doi: 10.1111/liv.15104. PMID: 34811877
Guazzi GC, Federico A
Acta Neurol (Napoli) 1992 Aug-Dec;14(4-6):469-84. PMID: 1293989

Recent clinical studies

Etiology

Honey NK, Miller AL, Shows TB
Am J Med Genet 1981;9(3):239-53. doi: 10.1002/ajmg.1320090310. PMID: 7282783

Diagnosis

Lee BH, Kim YM, Kim JH, Kim GH, Lee BS, Kim CJ, Yoo HJ, Yoo HW
Brain Dev 2014 Feb;36(2):171-5. Epub 2013 Feb 19 doi: 10.1016/j.braindev.2013.01.012. PMID: 23433491
Loonen MC, Reuser AJ, Visser P, Arts WF
Clin Genet 1984 Aug;26(2):139-49. doi: 10.1111/j.1399-0004.1984.tb00804.x. PMID: 6432381
Matsuo T, Egawa I, Okada S, Suetsugu M, Yamamoto K, Watanabe M
J Neurol Sci 1983 Jan;58(1):45-55. doi: 10.1016/0022-510x(83)90109-0. PMID: 6405017
Honey NK, Miller AL, Shows TB
Am J Med Genet 1981;9(3):239-53. doi: 10.1002/ajmg.1320090310. PMID: 7282783

Therapy

Bender HU, Borggraefe I, Coppenrath E, Maier EM
Neurology 2019 Jul 23;93(4):168-169. doi: 10.1212/WNL.0000000000007835. PMID: 31332084

Clinical prediction guides

Loonen MC, Reuser AJ, Visser P, Arts WF
Clin Genet 1984 Aug;26(2):139-49. doi: 10.1111/j.1399-0004.1984.tb00804.x. PMID: 6432381
Honey NK, Miller AL, Shows TB
Am J Med Genet 1981;9(3):239-53. doi: 10.1002/ajmg.1320090310. PMID: 7282783

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