Sorted By Test Name - Mayo Medical Laboratories

PK
8659
of PDHC deficiency is a defect in the E1 alpha gene, located on the X chromosome. It is considered an
X-linked dominant condition in that both females and males with an E1 alpha gene mutation are affected
with PDHC deficiency. Mutations in the E1 alpha gene are typically de novo. The most important initial
diagnostic test is the measurement of blood and cerebrospinal fluid lactate and pyruvate, along with a
lactate-to-pyruvate (L:P) ratio (typically normal ratio with elevated lactate and pyruvate). Additionally,
plasma amino acids (AAQP/9265 Amino Acids, Quantitative, Plasma) may detect an increase in alanine.
A diagnosis of PDHC deficiency depends on the measurement of enzyme activity in cells or tissues, most
commonly in skin fibroblasts.
Useful For: Evaluation of patients with a clinical suspicion of a pyruvate dehydrogenase complex
deficiency or an energy metabolism disorder
Interpretation: When below-normal enzyme activities 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.
Reference Values:
PDHC, ACTIVATED
Range: 1.63-3.61 mU/mg protein
PDHC, INACTIVATED
Range: 0.18-2.18 mU/mg protein
Reference values apply to all ages.
Clinical References: 1. Patel KP, Obrien TW, Subramony SH, et al: The spectrum of pyruvate
dehydrogenase complex deficiency: clinical, biochemical and genetic features in 371 patients. Mol Gen
Met 2012;106:385-394 2. Robinson BH: Lactic acidemia: disorders of pyruvate carboxylase and pyruvate
dehydrogenase. In The Online Metabolic and Molecular Basis of Inherited Disease. Edited by CR Scriver,
AL Beaudet, WS Sly, D Valle. Available from URL: http://dx.doi.org/10.1036/ommbid.128 Retrieved
6/25/12
Pyruvate Kinase, Erythrocytes
Clinical Information: Deficiencies of most of the enzymes of the Embden-Meyerhof (glycolytic)
pathway, including pyruvate kinase (PK), have been reported. PK deficiency, although rare, is the
erythrocyte enzyme deficiency most frequently found to be a cause of congenital nonspherocytic
hemolytic anemia. It is an autosomal recessive disorder. Thus, the parents of affected patients are
heterozygotes. Patients usually present during early childhood with anemia, icterus, and splenomegaly.
Hemolytic disease of the newborn is common in persons with PK deficiency.
Useful For: Work-up of cases of nonspherocytic hemolytic anemia Investigating families with
pyruvate kinase deficiency to determine inheritance pattern and for genetic counseling
Interpretation: Most pyruvate kinase (PK) deficient patients have 5% to 25% of normal activity.
Elevated PK concentrations can be found in those patients with younger erythrocyte population. This may
be due to the patient being a newborn or young red cells are being produced in response to the anemia
(reticulocytosis).
Reference Values:
6.7-14.3 U/g hemoglobin
Clinical References: Beutler E: Hereditary nonspherocytic hemolytic anemia: pyruvate kinase
deficiency and other abnormalities. In Hematology. 4th edition. Edited by WJ Williams, E Beutler, AJ
Erslev, MA Lichtman. New York, McGraw-Hill Information Services Company, Health Professions
Division, 1990, pp 606-612
Current as of January 4, 2013 7:15 pm CST 800-533-1710 or 507-266-5700 or MayoMedicalLaboratories.com Page 1514