Primary ciliary dyskinesia: improving the diagnostic approach.
OBJECTIVE
The diagnosis of primary ciliary dyskinesia (PCD) has relied on analysis of ciliary motility and ultrastructure; however, these tests are not readily available and have not been standardized. Consequently, the diagnosis of PCD may be delayed or missed or made incorrectly. This review outlines the potential utility of new diagnostic tests, including measurement of nasal nitric oxide production and systematic analysis for mutations in genes encoding ciliary proteins.


RESULTS
Clinical manifestations of PCD have been expanded to include neonatal respiratory distress and heterotaxy. Measurement of nasal nitric oxide has emerged as a useful screening test for PCD based on the very low levels in PCD (approximately 1/10 of normal values). Genetic testing is emerging for PCD and demonstrates extensive genetic heterogeneity. Some genes and gene mutations involved in PCD have been defined. Approximately one-third of PCD cases have identifiable gene mutations in one of six different genes. An international effort is focused on defining PCD-causing defects in other genes.


CONCLUSIONS
The incorporation of nasal nitric oxide measurement as a screening test to define probable PCD cases and gene mutation analysis to make a definitive diagnosis of PCD should enhance diagnostic evaluation of PCD.
Leigh
Margaret W
MW
Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7220, USA. mleigh@med.unc.edu
Zariwala
Maimoona A
MA
Knowles
Michael R
MR
D056444:Axonemal Dyneins; D001944:Breath Tests / Q000379:methods*; D002648:Child; D002923:Cilia / Q000648:ultrastructure; D004247:DNA / Q000032:analysis* / Q000235:genetics; D004252:DNA Mutational Analysis / Q000379:methods; D003937:Diagnosis, Differential; D004398:Dyneins / Q000235:genetics*; D006801:Humans; D007619:Kartagener Syndrome / Q000175:diagnosis*; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D009296:Nasal Cavity; D009569:Nitric Oxide / Q000032:analysis*
C425071:DNAI1 protein, human; D009569:Nitric Oxide; D004247:DNA; D056444:Axonemal Dyneins; C497507:DNAH5 protein, human; D004398:Dyneins