NKX2-5 and congenital heart defects, multiple types: Germinal mutations in thyroid related transcription factors NKX2.1, FOXE1, PAX-8, and NKX2.5 have been identified in only 3% of patients with sporadic CHTD and linkage analysis excluded these genes in some multiplex families with CHTD, which is consistent with a complex genetic contribution [10].