In addition, however, although it can be predicted that dermal fibroblasts will undergo spontaneous loss of the second allele of TSC1/TSC2 at multiple sites, the distribution of angiofibromas in TSC subjects is highly circumscribed, suggesting that other factors influence the development of these lesions beyond loss of TSC1 or TSC2. The gene discussed is TSC1; the disease is Angiofibromas.