Sorted By Test Name - Mayo Medical Laboratories

CDTA
82425
the a-oligosaccharide/di-oligosaccharide transferrin ratio, the tri-sialo/di-oligosaccharide transferrin ratio,
the apolipoprotein CIII1/apolipoprotein CIII2 ratio and the apolipoprotein CIII0/apolipoprotein CIII2
ratio. The report will include the quantitative results and an interpretation. The CDG profile is categorized
in four types: The CDG type I profile when mono-oligosaccharide/di-oligosaccharide transferrin ratio,
and/or the a-oligosaccharide/di-oligosaccharide transferrin ratio are abnormal. This group should have the
Apoliprotein C-III profile within the normal ranges, because in CDG type I the golgi system is not
affected. The CDG type II profile when the tri-sialo/di-oligosaccharide transferrin ratio is abnormal. In
this category the Apolipoprotein C-III profile will have two scenarios: A. the apolipoprotein
CIII1/apolipoprotein CIII2 ratio and/or the apolipoprotein CIII0/apolipoprotein CIII2 ratio will be
abnormal when the defect is most likely glycan processing in the Golgi apparatus therefore the COG
defect is likely; and B. the apolipoprotein CIII1/apolipoprotein CIII2 ratio and/or the apolipoprotein
CIII0/apolipoprotein CIII2 ratio are normal, in this cases most likely the defects do not involve the Golgi
system, thus the molecular defect is different from A. The CDG mixed type profile (Type I and II
together) in this type of profile one can have abnormal the tri-sialo/di-oligosaccharide transferrin ratio
with the mono-oligosaccharide/di-oligosaccharide transferrin ratio and/or the
a-oligosaccharide/di-oligosaccharide transferrin ratio abnormal, and may have the apolipoprotein
CIII1/apolipoprotein CIII2 ratio and the apolipoprotein CIII0/apolipoprotein CIII2 ratio normal or
abnormal, depending if the defects involve Golgi apparatus. When the profile can not be categorized
following the above classification, all the abnormal transferrin and or Apo-CIII species will be reported
descriptively according to the molecular mass stating the possible structures Reports of abnormal results
will include recommendations for additional biochemical and molecular genetic studies to more precisely
identify the correct form of CDG. Treatment options, the name and telephone number of contacts who
may provide studies at Mayo Clinic or elsewhere, and a telephone number for one of the laboratory
directors (if the referring physician has additional questions) will be provided.
Reference Values:
MONO-OLIGOSACCHARIDE/DI-OLIGOSACCHARIDE
< or =0.100
A-OLIGOSACCHARIDE/DI-OLIGOSACCHARIDE
< or =0.050
Clinical References: 1. Jaeken J, Matthijs G: Congenital disorders of glycosylation: a rapidly
expanding disease family. Annu Rev Genomics Hum Genet 2007;8:261-278 2. Freeze HH: Congenital
disorders of glycosylation: CDG-I, CDG II, and beyond. Curr Mol Med 2007;7:389-396 3. Patterson MC:
Screening for "prelysosomal disorders": carbohydrate-deficient glycoprotein syndromes. J Child Neurol
1999;14(Suppl 1):S16-S22 4. Stibler H, Jaeken J: Carbohydrate deficient serum transferrin in a new
systemic hereditary syndrome. Arch Dis Child 1990;65:107-111 5. Freeze HH: Disorders in protein
glycosylation and potential therapy - tip of an iceberg. J Pediatr 1998;133:593-600 6. Stibler H, Borg S:
Evidence of a reduced sialic acid content in serum transferrin in male alcoholics. Alcohol Clin Exp Res
1981;5:545-549
Carbohydrate Deficient Transferrin, Adult, Serum
Clinical Information: Chronic alcoholism causes a transient change in the glycosylation pattern of
transferrin where the relative amounts of disialo- and asialotransferrin (carbohydrate deficient transferrin:
CDT) are increased over the amount of normally glycosylated tetrasialotransferrin. This recognition led to
the use of CDT in serum as marker for chronic alcohol abuse. CDT typically normalizes within several
weeks of abstinence of alcohol use. However, it is important to recognize that there are other causes of
abnormal CDT levels, which include congenital disorders of glycosylation (CDG) and other genetic and
non-genetic causes of acute or chronic liver disease. CDT testing alone is not recommended for general
screening for alcoholism; however, when combined with other methods (ie, gamma-glutamyltransferase,
mean corpuscular volume, patient self-reporting) clinicians can expect to identify 90% or more of patients
who consume a large amount of alcohol.
Useful For: An indicator of chronic alcohol abuse
Interpretation: Patients with chronic alcoholism may develop abnormally glycosylated transferrin
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