Pathogenesis of telangiectasia in scleroderma

Scleroderma (progressive systemic sclerosis) is a systemic autoimmune disor der characterised by skin sclerosis, calcinosis and changes in microvascula ture. The etiology of the disease is unknown but both genetic and environme ntal factors have been implicated. Telangiectasia (macroscopically visible dilated skin vessels) occurring primarily on the hands and face, are a prom inent feature in scleroderma and are present in the majority of patients. S imilarly, telangiectasia are found in patients with hereditary hemorrhagic telangiectasia (HHT), a mutational disorder of the germline genes endoglin and ALK-1, members of the TGF beta receptor family, expressed on endothelia l cells. Our study investigated the number, distribution and microscopic ch aracteristics of telangiectasia in both limited (n = 29) and diffuse sclero derma (n = 9) and compared findings with 3 patients with HHT. In limited sc leroderma, the mean number of telangiectasia (hand and face) was 36 (0-150) compared with 23 (0-135) in diffuse scleroderma. A significant correlation was observed between the number of telangiectasia on the face and on the h ands (p = 0.014). The total number of telangiectasia correlated significant ly with the disease duration (p = 0.009). The spatial distribution of the t elangiectasia appeared to be random on both hands and foreface in contrast with the distribution of subcutaneous calcification of the hands which occu rred predominantly on the distal and flexor surfaces of the first, second a nd fifth digits. Nailfold microscopic capillaroscopy was performed on 12 pa tients. No significant correlation was observed between capillary diameter or density and with total number of telangiectasia observed macroscopically . The distribution and microscopic appearance of telangiectasia in sclerode rma appeared very similar to those observed in HHT. In view of these simila rities we therefore conclude that telangiectactic development in scleroderm a may be associated with disorders of the TGFb receptor family proteins fou nd on the microvasculature.