Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

KPCRP
89675
Clinical Information: Ullrich-Turner syndrome (UTS), also called Turner syndrome, is a genetic
disorder associated with the apparent loss of a sex chromosome. Routine cytogenetic methods have
identified 3 types of chromosomal abnormalities in UTS patients: loss of an entire X chromosome (45,X),
structural X chromosome abnormalities, and mosaicism with an X or Y abnormality. In mosaicism, 2 or
more populations of cells with different karyotypes are present (eg, 45,X/47,XXX). The incidence of UTS
is approximately 1/3,000 newborn girls. Many of these patients demonstrate the 45,X karyotype. About
30% to 50% are mosaic, with either a 45,X/46,XX karyotype or a structurally abnormal X chromosome.
Fewer than 15% of patients with UTS appear to have mosaicism with a 46,XY cell population or a Y
chromosome rearrangement. Identifying the mosaic status of patients with UTS is of clinical importance
because phenotypic expression and clinical management are dependent upon the karyotype result. Patients
with a Y chromosome have a 15% to 25% increased risk of gonadoblastoma.
Useful For: This test provides a sensitive method for identifying sex chromosome mosaicism (ie, low
level detection)
Interpretation: An XX clone is confirmed when > or =1.0% cells display with 2 X chromosome
signals. An XY clone is confirmed when > or =0.6% cells display a 1 X and 1 Y signal pattern. Females
with a 45,X/46,XX karyotype have no increased risk of gonadoblastoma and generally have a more
moderate expression of Turner syndrome features than females with a nonmosaic 45,X karyotype. The
presence of a Y chromosome confers increased risk of gonadoblastoma.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Canto P, Kofman-Alfaro S, Jiminez AL, et al: Gonadoblastoma in Turner
syndrome patients with nonmosaic 45,X karyotype and Y chromosome sequences. Cancer Genet
Cytogenet 2004;150:70-72 2. Gravholt CH, Fedder J, Naeraa RW, Muller J: Occurrence of
gonadoblastoma in females with Turner syndrome and Y chromosome material: a population study. J Clin
Endocrinol Metab 2000;85:3199-3202 3. Sybert VP, McCauley E: Turner syndrome. N Engl J Med
2004;351:1227-1238
KPC (blaKPC) in Enterobacteriaceae, Molecular Detection, PCR
Clinical Information: Resistance to carbapenem antibiotics, by means of the enzyme KPC
(Klebsiella pneumoniae carbapenemase), produced by Klebsiella pneumoniae and other members of the
Enterobacteriaceae family, is becoming more common. The gene blaKPC encodes KPC production. In
addition to KPC production, several other genetic factors can cause resistance to carbapenems including
production of other carbapenemases, plasmid-encoded AmpC beta-lactamases, or extended
beta-lactamase (ESBL) combined with decreased membrane permeability. It is important to know if an
isolate is resistant to carbapenems for proper reporting of antimicrobial susceptibility results and, in turn,
determining proper antimicrobial therapy. Detection of carbapenemases by the conventional phenotypic
method (ie, modified Hodge test) may be subjective and is not rapid. Testing for the minimum inhibitory
concentration (MIC) determines the level of resistance of the isolate, but not the mechanism causing the
resistance. Real-time PCR is a sensitive, specific, and rapid means of detecting of a specific portion of the
gene encoding KPC production.
Useful For: Assessing pure isolates of Klebsiella pneumoniae or other members of the
Enterobacteriaceae for carbapenem resistance
Interpretation: A positive KPC (Klebsiella pneumoniae carbapenemase) PCR indicates that the isolate
tested carries blaKPC. Carbapenems (doripenem, ertapenem, imipenem, meropenem) should not be used
to treat these isolates. A negative result indicates the absence of detectable DNA, however false negative
results may occur due to inhibition of PCR or sequence variability underlying primers and/or probes. The
assay detects the 13 blaKPC genotypes described as of June 2012.
Reference Values:
Not applicable
Clinical References: 1. Real-Time PCR Procedure for Detection of Genes Encoding KPC
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