TSC1 and hamartoma: In particular, whereas genetic defects in TSC1 and TSC2 may lead to hamartomas, a non-neoplastic proliferative disorder [36], [37], the deletion of Tsc1 did not have a demonstrable impact on normal biology of the skin, nor did we observe spontaneous tumor formation in mice with conditional Tsc1 deletion in the skin after more than one year of observation (not shown).