Mucolipidosis Type IV via the MCOLN1 Gene
Summary and Pricing 
Test Method
Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes| Test Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
|---|---|---|---|---|---|
| 7903 | MCOLN1 | 81479 | 81479,81479 | $990 | Order Options and Pricing |
Pricing Comments
Testing run on PG-select capture probes includes CNV analysis for the gene(s) on the panel but does not permit the optional add on of exome-wide CNV analysis. Any of the NGS platforms allow reflex to other clinically relevant genes, up to whole exome or whole genome sequencing depending upon the base platform selected for the initial test.
An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.
This test is also offered via a custom panel (click here) on our exome or genome backbone which permits the optional add on of exome-wide CNV or genome-wide SV analysis.
Turnaround Time
3 weeks on average for standard orders or 2 weeks on average for STAT orders.
Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.
Targeted Testing
For ordering sequencing of targeted known variants, go to our Targeted Variants page.
Clinical Features and Genetics
Clinical Features
Mucolipidosis Type 4 (MLIV) is a neurodegenerative disorder characterized by neurodevelopmental delay, encephalopathy, ophthalmological anomalies and achlorhydria (Berman et al. J Pediatr 84(4):519-526, 1974; Schiffmann et al. Proc Natl Acad Sci USA 95(3):1207-1212, 1998). Normal lysosomal enzyme activities in the presence of lysosomal inclusions with heterogeneous lipid and protein contents distinguishes MLIV from mucolipidoses types I, II and III (Geer et al. Pediatr Neurol 42(3):223-226, 2010).
Two clinical subtypes of MLIV are recognized based on the age of onset, severity and a number of atypical clinical features.
1) Typical MLIV is the most severe and frequent form of the disease. Symptoms usually begin during the first year of life and include difficulty in speaking and walking as the result of psychomotor developmental delay, spasticity, hypotonia, bilateral corneal opacity, strabismus, retinal degeneration and optic atrophy. MRI findings include a thin corpus callosum and white matter abnormalities in the early stage of the disease, and cerebellar atrophy later on (Frei et al. Neurology 51(2):565-569, 1998). Disease progression is generally slow, except for the ophthalmological manifestations which may ultimately lead to blindness (Geer et al., 2010).
2) Atypical MLIV is characterized by later onset, mild symptoms, and dysmorphic features which are usually absent in the typical form and include clinodactyly, partial syndactyly, puffy eyelids and coarse face. Corneal clouding may be absent (Chitayat et al. Am J Med Genet 41(3):313-318, 1991).
MLIV is pan-ethnic. It is however most prevalent in the Ashkenazi Jewish population with a disease prevalence of about 1:40,000 live births and a carrier rate of 0.01 (Bach G et al. Hum Mutat 26(6):591, 2005).
Genetics
MLIV is inherited in an autosomal recessive manner, and results from mutations in the MCOLN1 gene (Bargal et al. Nat Genet 26(1):118-123, 2000; Bassi et al. Am J Hum Genet 67(5):1110-1120, 2000; Sun et al. Hum Mol Genet 9(17):2471-2478, 2000). To date, about 30 mutations have been reported and include all types, although missense mutations constitute the majority. Two mutations account for about 95% of all mutations detected in the Ashkenazi Jewish population and include a splicing mutation (c.406-2A>G) and a 6.4-kb deletion (g.511_6943del) that spans the first six exons.
The MCOLN1 gene encodes mucolipin-1 protein, an integral membrane protein and member of the transient potential receptor (TRP) gene family. It is postulated to be involved in the regulation of membrane trafficking of proteins and lipids in the endocytic pathway (LaPlante et al. Biochem Biophys Res Commun 322(4):1384-1391, 2004).
Clinical Sensitivity - Sequencing with CNV PG-Select
This test will detect mutations in ~ 99% of patients with mutations other than the common deletion in the Ashkenazi Jewish population with a clinical diagnosis of MLIV (Schiffmann et al. GeneReviews, 2010).
Testing Strategy
This test provides full coverage of all coding exons of the MCOLN1 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.
Indications for Test
Children with mild to moderate developmental delay, ophthalmological abnormalities with or without corneal clouding, elevated blood gastrin levels as the result of achlorhydria, and inclusion bodies in skin biopsy; potential heterozygous carriers of a recessive pathogenic MCOLN1; and partners of individuals known to be heterozygous carriers.
Children with mild to moderate developmental delay, ophthalmological abnormalities with or without corneal clouding, elevated blood gastrin levels as the result of achlorhydria, and inclusion bodies in skin biopsy; potential heterozygous carriers of a recessive pathogenic MCOLN1; and partners of individuals known to be heterozygous carriers.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| MCOLN1 | 605248 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Disease
| Name | Inheritance | OMIM ID |
|---|---|---|
| Ganglioside Sialidase Deficiency | AR | 252650 |
Citations
- Bach, G. et al. (2005). "The frequency of mucolipidosis type IV in the Ashkenazi Jewish population and the identification of 3 novel MCOLN1 mutations." Hum Mutat 26(6):591. PubMed ID: 16287144
- Bargal, R. et al. (2000). "Identification of the gene causing mucolipidosis type IV." Nat Genet 26(1):118-123. PubMed ID: 10973263
- Bassi, M.T. et al. (2000). "Cloning of the gene encoding a novel integral membrane protein, mucolipidin-and identification of the two major founder mutations causing mucolipidosis type IV." Am J Hum Genet 67(5):1110-1120. PubMed ID: 11013137
- Berman, E.R. et al. (1974). "Congenital corneal clouding with abnormal systemic storage bodies: a new variant of mucolipidosis." J Pediatr 84(4):519-526. PubMed ID: 4365943
- Chitayat, D. et al. (1991). "Mucolipidosis type IV: clinical manifestations and natural history." Am J Med Genet 41(3):313-318. PubMed ID: 1789285
- Frei, K.P. et al. (1998). "Mucolipidosis type IV: characteristic MRI findings." Neurology 51(2):565-569. PubMed ID: 9710036
- Geer, J.S. et al. (2010). "Mucolipidosis type IV: a subtle pediatric neurodegenerative disorder." Pediatr Neurol 42(3):223-226. PubMed ID: 20159435
- LaPlante, J.M. et al. (2004). "Functional links between mucolipin-1 and Ca2+-dependent membrane trafficking in mucolipidosis IV." Biochem Biophys Res Commun 322(4):1384-1391. PubMed ID: 15336987
- Schiffman, R. et al. (2010). "Mucolipidosis IV." GeneReviews. PubMed ID: 20301393
- Schiffmann, R. et al. (1998). "Constitutive achlorhydria in mucolipidosis type IV." Proc Natl Acad Sci USA 95(3):1207-1212. PubMed ID: 9448310
- Sun, M. et al. (2000). "Mucolipidosis type IV is caused by mutations in a gene encoding a novel transient receptor potential channel." Hum Mol Genet 9(17):2471-2478. PubMed ID: 11030752
Ordering/Specimens
Ordering Options
We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.
myPrevent - Online Ordering
- The test can be added to your online orders in the Summary and Pricing section.
- Once the test has been added log in to myPrevent to fill out an online requisition form.
- PGnome sequencing panels can be ordered via the myPrevent portal only at this time.
Requisition Form
- A completed requisition form must accompany all specimens.
- Billing information along with specimen and shipping instructions are within the requisition form.
- All testing must be ordered by a qualified healthcare provider.
For Requisition Forms, visit our Forms page
If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.
Specimen Types
Specimen Requirements and Shipping Details
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