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AACSF
81934
Eighth edition. Edited by CR Scriver, AL Beaudet, WS Sly, et al: New York, McGraw-Hill, 2001, pp
1667-2105
Amino Acids, Quantitative, Spinal Fluid
Clinical Information: Many genetic errors affecting amino acid metabolism have been identified.
Defects of either transport or catalytic activity of enzymes involved in this pathway result in accumulation
or excessive loss of 1 or more amino acids in biological fluids. Inborn errors of amino acid metabolism
can manifest themselves at anytime in a personâ€s life, but most become evident in infancy and early
childhood. Affected patients may have failure to thrive, neurological symptoms, digestive problems,
locomotor retardation, and a wide spectrum of laboratory findings. If not diagnosed promptly and treated
properly, these disorders can result in poor growth, mental retardation, and death. Cerebrospinal fluid
(CSF) specimens are highly informative for a subset of these conditions, such as nonketotic
hyperglycinemia and serine biosynthesis defects. CSF specimens are most informative when a plasma
specimen is drawn at the same time and the ratio of the amino acid concentrations in CSF to plasma is
calculated.
Useful For: Evaluating patients with possible inborn errors of amino acid metabolism, in particular
nonketotic hyperglycemia and serine biosynthesis defects, especially when used in conjunction with
concomitantly drawn plasma specimens
Interpretation: When no significant abnormalities are detected, a simple descriptive interpretation is
provided. When abnormal results are detected, a detailed interpretation is given. This interpretation
includes an overview of the results and their significance, a correlation to available clinical information,
elements of differential diagnosis, and recommendations for additional biochemical testing and in vitro
confirmatory studies (enzyme assay, molecular analysis), name and phone number of key contacts who
may provide these studies at Mayo Clinic or elsewhere, and the telephone number to reach one of the
laboratory directors in case the referring physician has additional questions.
Reference Values:
CSF Amino Acid Reference Values Age Groups
(nmol/mL)
< or =31 Days
(n=73)
Phosphoserine (PSer)
Phosphoethanolamine (PEtN)
Taurine (Tau) 8-48
32 Days-23 Months
(n=88)
2-18 Years (n=189) > or =19 Years
(n=32)
Asparagine (Asn) 8-34 5-16 5-20
Serine (Ser) 44-136 26-71 21-51 19-40
Hydroxyproline (Hyp)
Glycine (Gly) 5-115
Glutamine (Gln) 467-1832 301-1128 326-1092 380-1348
Aspartic Acid (Asp)
Ethanolamine (EtN) 11-193 7-155 7-153 7-153
Histidine (His) 11-70 9-28 9-21 9-28
Threonine (Thr) 32-143 11-77 14-38 23-57
Citrulline (Cit)
Sarcosine (Sar)
Beta-alanine (bAla)
Alanine (Ala) 24-124 16-53 12-34 19-60
Current as of January 4, 2013 7:15 pm CST 800-533-1710 or 507-266-5700 or MayoMedicalLaboratories.com Page 115