Congenital Disorder of Glycosylation Ia (PMM2) Sequencing
| Disorder | Congenital Disorder of Glycosylation Ia (CDG Ia) | |
| Gene Name | PMM2 | |
| Clinical info | Congenital disorder of glycosylation (CDG) Ia is an autosomal recessive disorder caused by a deficiency of phosphomannomutase. This enzyme normally catalyzes the conversion of mannose-6-phosphate to mannose-1-phosphate. This step is required for the addition of N-linked sugars to proteins. Patients will present with hypotonia and developmental delay along with other symptoms including failure to thrive, abnormal fat distribution, seizures, stroke-like episodes and/or esotropia. Clinical presentation ranges from significantly affected infants to adolescents and adults with more minor involvement. | |
| Indications | Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis. | |
| Detection | Sequencing of the gene will detect over 95% of the causative mutations in patients with CDG Ia. | |
| Associated Tests | Transferrin isoelectric focusing screen CDG Ib Molecular testing Molecular testing for CDG Ic |
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| 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 | 21 days | |
| Prenatal testing | Prenatal diagnosis is available if the familial mutations are 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 |
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| Cost | $1000 for sequencing $350 for known mutation |
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| 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. | |
Form Needed
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Kellie King, MS, CGC
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.