5_prime_UTR_variant 5_prime_UTR_premature_start_codon_variant kareneilbeck 2013-07-30T04:36:25Z sequence SO:0001983 A 5' UTR variant where a premature start codon is introduced, moved or lost. Requested by Andy Menzies at the Sanger. This isn't necessarily a protein coding change. A premature start codon can effect the production of a mature protein product by providing a competing translation start point. Some genes balance their expression this way, eg THPO requires the presence of a premature start to limit expression, its loss leads to Familial thrombocythemia. 5' UTR premature start codon variant