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Diagnostic Services

Genetics Lab


I-Cell Disease Enzyme Assay

I-Cell disease also known as Mucolipidosis II (ML II) is an inherited lysosomal storage disorder. In I-cell disease, many lysosomal enzymes are missing because the enzymes are lacking a signal that is necessary for them to get inside the lysosome. Instead of getting into the lysosome and breaking down the molecules found there, the enzymes are found outside the lysosome. This leads to the build-up of molecules inside the lysosome.

I-Cell disease is closely related to Pseudo-Hurler Polydystrophy (Mucolipidosis III). Both disorders are “targeting “ defects. Pseudo-Hurler Polydystrophy disease presents with much less severe clinical findings. The enzyme that is responsible for putting the targeting signal on the lysosome enzymes implicated in I-Cell disease and Pseudo-Hurler Polydystrophy is N-acetylglucosamine-1-phototransferase.

Test Name: I-Cell disease enzyme assay
Test Code:
I Cell
Test Description:
Total hexosaminidase enzyme is measured in serum. The activity is elevated activity in patient with I-cell disease.
Mucolipidosis type II; mucolipidosis; I-cell; I cell
This test is used to diagnose I-cell disease in a symptomatic individual. This test is not appropriate for determining carrier status or for prenatal diagnosis.
Related Tests: Oligosaccharides, Urine  
This test is used to screen patients with neurodegenerative symptoms suggestive of a glycoprotein storage disorder.

Clinical Links: I-Cell Disease OMIM Entry
Turnaround Time:
7 days
Spectrophotometric enzyme assay
Reference Range:
Interpretive report is provided.
Consent Form:
Sample Requirements: Type
Whole Blood: 2ml, red or gold top tube.
Fibroblasts: 2 T-25 flasks.
Skin biopsy: 2-4mm punch biopsy

Spin and freeze serum.

Ship frozen serum overnight on dry ice. Ship fibroblasts or skin biopsy in appropriate transport/culture medium
Samples Received:
Mon Fri 8 am - 5 pm PST
Special Considerations:
Same test as serum Hexosaminidase Levels (A + Total). If fresh skin biopsy is submitted, Fibroblast Culture (CH-SKIN) must be ordered separately. Please call to discuss.
Please e-mail Client Services or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Client Services or call at 206-987-2617 with any billing questions