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mucolipidosis
Classification: includes four diseases:
1) Mucolipidosis 1 (sialidosis)
2) Mucolipidosis 2 (I-cell disease) {severe form}
3) Mucolipidosis 3 (pseudo-Hurler polydystrophy)
4) Mucolipidosis 4 {95% with severe form}
Epidemiology:
-> some forms are more common among Ashkenazi Jews & French Canadians.
Pathology:
1) bone & joint damage
2) injury to other organs
3) peculiar fibroblast inclusions (type 2)
4) type 3C retains full transferase activity on synthetic substrates but lacks activity on lysosomal hydrolases (regulatory subunit GNPTG mutation)
Genetics:
1) mucolipidosis 2 & 3A
a) autosomal recessive
b) caused by mutation in GNPTAB gene
2) mucolipidosis 3C
a) autosomal recessive
b) caused by mutation in GNPTG gene
3) mucolipidosis 4
a) autosomal recessive
b) caused by mutation in MCOLN1 gene
Clinical manifestations:
1) mental retardation (may be mild in type 3C)
2) impairment in the development of psychomotor skills
3) stiff or deformed joints
4) short stature
5) scoliosis
6) claw-like hands
7) hip joint deterioration
8) fatigue
9) abnormalities of the skull & face
- hyperplastic gums (type 2)
10) frequent respiratory infections
11) clouding of the cornea
12) congenital dislocation of the hip (type 2) severe dysostosis multiplex of the hip (type 3C)
Laboratory:
1) prenatal screening tests available
- MCOLN1 genotyping
2) no excessive mucopolysacchariduria (type 2)
3) elevated serum lysosomal enzyme levels &/or decreased lysosomal enzyme levels in cultured fibroblasts
4) see ARUP consult [1]
Management:
1) treatment is symptomatic
2) treat infections
3) surgery to correct bone or joint damage
4) prognosis
a) based on the severity of the symptoms, which can range from relatively moderate to life threatening
b) some forms of mucolipidoses can be fatal
- type 2
Related
mucolipin-1; MG-2; mucolipidin (MCOLN1 ML4 MSTP080)
N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase)
N-acetylglucosamine-1-phosphotransferase subunits alpha/beta precursor (GNPTAB, GlcNAc-1-phosphotransferase alpha/beta, UDP-N-acetylglucosamine-1-phosphotransferase alpha/beta, stealth protein GNPTAB)
Specific
fucosidosis
General
lipid metabolism, inborn error; lipid storage disease; lipidosis
lysosomal storage disease
Database Correlations
OMIM correlations
References
- ARUP Consult: Jewish Genetic Disease
The Physician's Guide to Laboratory Test Selection & Interpretation
- Ashkenazi Jewish Genetic Diseases Carrier Screening Algorithm
https://arupconsult.com/algorithm/jewish-genetic-diseases-carrier-screening-algorithm
- Ashkenazi Jewish Genetic Diseases Panel
https://arupconsult.com/ati/ashkenazi-jewish-genetic-diseases-panel
- National Institute of Neurological Disorders and Stroke (NINDS)
NINDS Mucolipidoses Information Page
https://www.ninds.nih.gov/Disorders/All-Disorders/Mucolipidoses-Information-Page
- Mucolipidosis type IV
http://ghr.nlm.nih.gov/condition/mucolipidosis-type-iv