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Bhd Syndrome Essay

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1.1 Birt-Hogg-Dubé Syndrome
Birt-Hogg-Dubé (BHD) syndrome (OMIM 135150) is a rare, autosomal dominant, hamartoma disorder which is characterized by benign tumours of the hair follicle (fibrofolliculomas), lung cysts and pneumothorax (collapsed lung), and renal neoplasia. BHD was first described in 1977 by three Canadian doctors – Birt, Hogg and Dubé (Birt et al. 1977). The syndrome had also been identified 1975 by Hornstein and Knickenberg (Hornstein & Knickenberg 1975) and there has been suggestion of renaming the disease to Hornstein-Birt-Hogg-Dubé, however due to confusion this name was never used.
A genome-wide linkage analysis using polymorphic microsatellite markers on a large Swedish family in 2001 mapped the BHD-associated locus to …show more content…

suggested that fibrofolliculomas arise from sebaceous glands rather than the hair follicles. They found that most of the epithelial strands making up the lesion are continuation of the sebaceous glands. This could possibly be as a result of ciliary dysfunction in either the sebaceous gland progenitor or stem cells, which in turn could explain the formation of skin lesions around the areas rich in sebaceous glands such as the nose and perinasal skin (Vernooij et al. 2013).
In 2010, Cocciolone et.al. suggested a connection between desmoplastic melanoma and BHD in a 58 year old patient as a result of mTOR up-regulation. There are 6 other cases of melanoma reported in patients with a BHD mutation; although quite possibly the event could be coincidental and a direct link cannot be confirmed (Cocciolone et al. 2010)(Leter et al. 2008).
The range of skin manifestation in BHD patients varies. Some patients do not develop any skin abnormalities at all whereas the number of fibrofolliculomas in other patients can differ from under 10 to over 100 (Toro et al. 1999).
Some skin abnormalities seen in BHD patients are quite similar to a few other genetic disorders shown in table …show more content…

in a study of 152 patients from 49 families in 1999 first described the presence of pulmonary cysts in BHD patients (Toro et al. 1999). Most of BHD patients are likely to develop pulmonary cysts and are susceptible to recurrent spontaneous pneumothorax. The study of 50 BHD families showed 88% of the families developed pulmonary cysts and 53% of the families had a history of pneumothorax. In another study, Toro et al. reported a 93% pulmonary cyst presence in BHD patients (Toro et al. 2007)(Toro et al. 2008). Pulmonary cysts are the most common BHD manifestation, seen in up to 90 % of patients (Predina et al. 2011). It has been suggested that the number of pulmonary cysts correlates with episodes of spontaneous pneumothoraces. Zbar et al. identified an increase in the risk of pneumothorax for BHD-affected individuals, which they postulated to be due to the presence of pulmonary cysts (Zbar et al.

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