Glossary of PCD Terminology
| asplenia |
Absence of the spleen |
| ATS |
American Thoracic Society. Primary professional organization for pulmonary researchers
(see CHEST for pulmonary clinicians) |
| basal body |
Structure at the base of each individual cilium. Although not yet implicated in PCD, basal body defects
are implicated in a number of other human diseases. |
| biliary atresia |
Rare in PCD--a condition present from the newborn period in which
the bile ducts inside or outside the liver do not have normal
openings. Bile becomes trapped in the liver, causing jaundice.
Without surgery the condition may cause death. |
| bronchiectasis |
Permanent damage to the bronchial tubes characterized by excessive
dilation of the tubes and recurrent pulmonary infection. Severe,
progressive bronchiectasis is the primary cause for lung transplant
in cystic fibrosis and PCD. |
| central pair/ central apparatus |
Microtubule structure at the center of the cilium. Defects in the
central apparatus are implicated in PCD. |
| CHEST (ACCP Chest) |
American College of Chest Physicians. Primary professional
organization for pulmonary clinicians (see ATS for pulmonary
researchers) |
| Chlamydamonas |
A ciliated algae. Most of what we know about human ciliary proteins
has come from research on this microorganism. |
| ciliary aplasia |
Failure of cilia to develop. |
| ciliary beat frequency |
Measurement of the actual beat pattern and frequency of respiratory
cilia. |
| cilium |
Single cilia |
| dextrocardia |
Refers to placement of the heart in a mirror-image position to the
right in the chest cavity, rather than to the typical left-sided
placement. |
| dynein arms |
Protein bundles that lie along the shaft of the cilium and work as
molecular motors to create the ciliary beat. Defects in either
inner or outer dynein arms
are the most common cause of PCD. |
| E.M.s |
Electron micrographs. High resolution and high magnication pictures
of the actual ultrastructure of cilia. |
| GDMCC |
Genetic Disorders of Mucociliary Clearance Consortium (GDMCC) aka
"The PCD Study." A group of four reseach hubs and 14 clinical sites
focused on data collection for PCD, atypical cystic fibrosis and
pseudohypoaldosteronism (PHA). |
| heterotaxy |
Any "abnormal" organ placement presentation. |
| hydrocephalus |
Rare in PCD--excess cerebral/spinal fluid or impaired fluid movement
in the ventricles of the brain leading to enlargement of the
ventricles and, if not treated, retardation. |
| IDA |
Inner dynein arm
|
| Kartagener syndrome |
Name for the subset of PCD patients who have
situs inversus totalis. Technically
organ arrangement that is not situs
inversus totalis (including
situs ambiguus) does
not qualify as Kartagener syndrome. |
| microtubules |
Ciliary structures arranged in pairs (doublets) that provide the
"backbone" of the cilia. Nine doublet microtubule pairs form a
circle around a central doublet (central pair) creating the classic
9 + 2 pattern seen in motile cilia. |
| NIH |
National Institutes of Health. Primary US government research
funding organization. ` |
| nitric oxide (NO) |
A gaseous byproduct of metabolism that can be measured in the
airways and sinuses. People with PCD have extremely low levels of
NO in their nasal cavities--a distinction that has encouraged the
use of nasal NO as a screening tool for PCD. Exhaled airway NO is
not predictive of PCD--nasal only. |
| nodal cilia |
A type of primary cilium that is found in the cells during embryonic
development. Although these cilia have no central pair, it is
believed that the motion of nodal cilia is responsible for organ
placement in embryonic development. |
| ODA |
Outer dynein arm |
| ORD |
Office of Rare Diseases. A branch of the NIH set up by
Congressional mandate in 2002 to ensure rare diseases were included
in research funding. |
| PAR |
Public Advisory Roundtable. An ATS committee made up of patient
advocacy groups. PAR funds patient-directed research initiatives. |
| PCD |
Primary ciliary dyskinesia--synonyms include
Kartagener syndrome,
immotile cilia syndrome
and ciliary aplasia
(note that disease names should not be in caps unless they are
eponymous or named for a person) |
| pectus excavatum |
A birth defect characterized by a depressed sternum. Pectus
excavatum is far more common in PCD than in the general population. |
| PHA |
Pseudohypoaldosteronism--a very rare salt-wasting disorder leading
to extremely thin and copious respiratory secretions. Usually
resolves in late childhood with appropriate therapy |
| PKD |
Polycystic kidney disease--an inherited condition related to defects
in primary cilia resulting in multiple cysts in the kidneys and
frequently requiring kidney transplant. |
| plasia or plastic |
Refers to physical development or growth. Aplasia refers to total
lack of development--people with ciliary aplasia have no cilia.
Hyperplasia refers to an overgrowth and hypoplasia to impaired
growth. |
| polysplenia |
Multiple spleens or "splenules" |
| primary cilia |
Sensory cilia found in nearly every cell of the body. Once thought
to be of little significance, they are now implicated in a number of
human diseases. Because primary cilia do not function as a group,
like respiratory cilia, some are also called "monocilia." |
| radial spoke |
A protein structure that connects the outer microtubule doublets to
the central pair. Defects in radial spokes are implicated in PCD |
| RDCRN |
Rare Diseases Clinical Research Network. The national program
established the the NIH
(National Institutes of Health) and the
ORD (Office of Rare Diseases) to
encourage research in rare diseases by creating a number of
consortia to share resources and data. PCD is one of the disorders
included and is represented in the Genetic Disorders of Mucociliary
Clearance Consortium (GDMCC). |
| situs ambiguus (or ambiguous) |
Unusual or random placement of abdominal or thoracic organs (e.g.
polysplenia, dextrocardia, midline liver,
etc.) |
| situs inversus |
Mirror image organ placement of some or all thoracic and/or
abdominal organs |
| situs inversus totalis |
Complete mirror-image placement of all thoracic and abdominal organs |
| situs solitus |
Abdominal and thoracic organ in the typical position. |
| syndrome |
A general term given to associated symptoms--generally when no
underlying cause has been determined. Once a cause has been
identified, the preference is to change the syndrome name to reflect
the underlying cause (e.g. Down syndrome is now referred to as
trisomy 21). |
| ventriculomegaly |
Rare in PCD--enlarged ventricles of the brain without excess
cerebral/spinal fluid. |