GM1 gangliosidosis (GLB1) Sequencing

Disorder GM1 Gangliosidosis
Gene Name GLB1
Clinical info

GM1 gangliosidosis is an autosomal recessive lysosomal storage disease with 3 clinical subtypes characterized by varying severity and age of onset. The primary features are neurodegeneration and skeletal abnormalities.

The classic or infantile type is most common and is usually present at birth. Coarse features, edema, failure to thrive, hypotonia and hepatomegaly are all characteristic findings. There is usually rapid progression of symptoms with the development of spasticity, seizures and general neurologic deterioration with death typically occurring by age 2.

Progressive cerebral deterioration is characteristic of the late infantile/juvenile form of GM1 gangliosidosis as well. However, symptoms usually start around 1 year with regression of gained skills such as speech and walking. Seizure management is often a major issue and these patients usually die between ages 3 and 7.

The chronic/adult subtype of GM1 is the least common subtype with the phenotype consisting of dystonia, progressive ataxia and cerebellar dysarthria. These patients do not have the typical dysmorphic facies.

Indications Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutation within a family to allow for carrier testing and prenatal diagnosis.
Associated Tests

Urine oligosaccharides is available in the Biochemical Diagnostic Lab and may be useful for screening for this disorder. Enzyme testing for beta-galactosidase activity is also available and can be used to help establish the diagnosis.

Specimen Requirements 5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 ml.
Transport The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.
Turnaround time 3 weeks
Prenatal testing Prenatal diagnosis is available if the familial mutation is known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.
CPT Codes Unknown mutation: 81479

Known mutation: 81479

Deletion/duplication analysis: 81229

Cost $1200 for full sequencing (unknown mutation)

$350 for known mutation

$700 for deletion/duplication analysis

Prenatal diagnosis for a known mutation is $1000.  Please contact the lab for more information.
Contact For further information contact This email address is being protected from spambots. You need JavaScript enabled to view it. , MS, Lab Counselor at 1-800-473-9411.

Molecular Diagnostic Lab

The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.

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