TCF20 and obesity due to melanocortin 4 receptor deficiency: The total cohort GWA for udder depth associated a novel SNP at BTA 5:113268242 located within an intron of Transcription Factor 20 (TCF20), which has been associated with human muscular dystrophy and postnatal overgrowth, such as tall stature, macrocephaly, and obesity [70].