Carrier screening or diagnostic testing for mucolipidosis type IV for individuals of Ashkenazi Jewish descent.
Polymerase Chain Reaction/Fluorescence Monitoring
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Specimens collected in sodium heparin or lithium heparin tubes.
Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
Background information for Mucolipidosis, Type IV (MCOLN1), 2 Variants:
Characteristics: Mucolipidosis type IV is characterized by early onset of severe psychomotor delay and progressive visual impairment due to corneal clouding and retinal degeneration. Affected individuals may occasionally learn to say a few words or walk independently. While most affected individuals remain neurologically static until age 30, about 15 percent will display neurological degeneration.
Incidence: 1 in 63,000 Ashkenazi Jewish individuals.
Inheritance: Autosomal recessive.
Cause: MCOLN1 pathogenic variants.
Variants Tested: g.511_6943del and c.406-2A>G.
Clinical Sensitivity: 95 percent in Ashkenazi Jewish individuals, 6 to 10 percent in other ethnicities.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Variants other than g.511_6943del and c.406-2A>G will not be detected. Diagnostic errors can occur due to rare sequence variations.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
|0051450||Mucolipidosis IV (MCOLN1), Allele 1||34658-5|
|0051451||Mucolipidosis IV (MCOLN1), Allele 2||34658-5|
|0051452||Mucolipidosis IV (MCOLN1), Interp||46965-0|
|2001329||Mucolipidosis IV (MCOLN1), Specimen||31208-2|