Congenital Disorders of Glycosylation
Type 1a
Congenital disorders of glycosylation (CDG) type 1a 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.
Mutational analysis of the phosphomannomutase gene (PMM2) detects
over 95% of the causative mutations in CDG1a patients. Identification of the
causative mutation/s in the proband can facilitate carrier detection in
interested family members.
Prenatal analysis can be performed provided the mutations in the
family are known. CVS samples will not be accepted.
Specimen requirements:
5 to 10 ml of peripheral blood
collected in an EDTA (lavendar top) Vacutainer tube is preferred. The minimal
blood needed for reliable DNA isolation is 3 ml. If necessary, ACD solution A
Vacutainer tubes (yellow top) may be submitted. Please contact the laboratory
for more information.
Transport:
Please contact Tim Wood (1-800-473-9411), the molecular diagnostic lab coordinator, for shipping
information. 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.
Analysis standards: Analysis will be
complete within 4 weeks of sample receipt. The lab director assesses the
quality and interpretation of results. Technical staff members independently
assess the quality and interpretation of the test. The Greenwood Genetic Center
Molecular Diagnostic Laboratory is CLIA certified and actively participates in
CAP proficiency surveys.
Reporting of Test Results: Test results with interpretation will be mailed and/or faxed
following completion of the test. Verbal reports will be telephoned to the
person(s) requesting the test when an abnormal test result occurs. Consultation
with the laboratory director and explanations of testing protocols will be
supplied upon request.
Unknown mutation:
-
CPT Codes: 83890, 83898 (x7), 83904 (x6),
83909 (x6), 83912
Known mutation:
-
CPT Codes: 83890, 83898, 83904
(x2), 83909, 83912
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