Primary ciliary dyskinesia

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Primary ciliary dyskinesia (PCD), also known as immotile ciliary syndrome or Kartagener Syndrome (KS), is a rare autosomal recessive genetic disorder caused by a defect in the action of the tiny hairs (cilia) lining the respiratory tract. Specifically, it is a defect in a gene coding for left-right dynein (lrd), a key structural protein in cilia.

Classification
When accompanied by the triad of situs inversus (reversal of the internal organs), chronic sinusitis, and bronchiectasis, it is known as Kartagener syndrome. Use of immotile ciliary syndrome is no longer favoured, as sperm in affected men often have some motility - the term was coined in the mistaken belief that they had none.

Signs and symptoms
The main consequence of impaired ciliary function is reduced or absent mucus clearance in the lungs, and susceptibility to chronic, recurrent respiratory infections, including sinusitis, bronchitis, pneumonia, and otitis media. Susceptibility to these infections can be drastically reduced by an early diagnosis, as treatment with various chest physiotherapy techniques during childhood helps prevent the lungs being damaged or colonised by infection during this vulnerable period. Many patients experience hearing loss and show symptoms of glue ear which demonstrate variable responsiveness to the insertion of myringotomy tubes or grommets. A poor sense of smell accompanies high mucus production in the sinuses. Infertility is common, but IVF techniques have been successful for some parents with PCD. Clinical progression of the disease is variable with lung transplantation required in severe cases. For most patients, aggressive measures to enhance clearance of mucus, prevent respiratory infections, and treat bacterial super infections are recommended. Although the true incidence of the disease is unknown, it is estimated to be 1 in 32.000, although the actual incidence may be as high as 1 in 150.000.

Causes
This disease in genetically inherited. Both inner and/or outer dynein arms are dysfunction and thus the axoneme structure lacks the ability to move. Axonemes are the elongated structures that make up cilia and flagella. The dysfunction of the cilia begins during the embryologic phase of development. Since the cilia aid in the movement of growth factors resulting in the normal rotation of the internal organs during early embryological development, 50% of these individuals will develop situs inversus, as the laterality of the internal organs is determined by chance.

History
The classical triad was first described by A. K. Zivert in 1904 while Kartagener published his first report in 1933.

Cardiac MRI
Images shown below are courtesy of RadsWiki and copylefted

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