Since all four family members affected with fibromatosis were double heterozygotes for the LMNA mutation c.736C>T (p.Gln246Stop) and ASTE1 c.230T>C (p.Val77Ala), it is possible that both Lamin A/C haploinsufficiency and an ASTE1 defect are required for disease. The gene discussed is LMNA; the disease is fibromatosis.